question stringlengths 37 38.8k | group_id stringlengths 2 6 | sentence_embeddings listlengths 768 768 |
|---|---|---|
<p>I have a very large dataset and about 5% random values are missing. These variables are correlated with each other. The following example R dataset is just a toy example with dummy correlated data.</p>
<pre><code>set.seed(123)
# matrix of X variable
xmat <- matrix(sample(-1:1, 2000000, replace = TRUE), ncol = ... | g58227 | [
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<p>From any generic sampling algorithm, one can derive an optimization algorithm.</p>
<p>Indeed, to maximize an arbitrary function $f: \textbf{x} \rightarrow f(\textbf{x})$, it suffices to draw samples from $g \sim e^{f/T}$. For $T$ small enough, these samples will fall near the global maximum (or local maxima in prac... | g35 | [
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<p>Does anybody has the
example of the program which
simulates Sequential Monte Carlo Algorithm?
In any software. I'm trying to write such
kind of program but there constantly are
question and problems I can't solve.
Regards</p> | g58228 | [
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<p>I have several time series that are each observations of the same phenomenon, for example:</p>
<blockquote>
<p>Observation 1: 10, 25, 36, 72, 80, ....</p>
<p>Observation 2: 32, 46, 78, 90, 100, ....</p>
<p>Observation 3: 12, 27, 34, 75, 36, ...</p>
<p>....</p>
<p>Observation 100: 7, 33, 45, 56... | g58229 | [
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<p>Using an average temperature data (Y1), I was trying to replicate the R command below as used in <em><a href="http://rads.stackoverflow.com/amzn/click/1441926135" rel="nofollow">Time Series Analysis With Applications in R</a></em> by Jonathan D. Cryer & Kung-Sik Chan, but I keep receiving an error message.
R Com... | g58230 | [
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<p>I am regressing different dependent variables using same set of predictors for all dependent variables such as </p>
<pre><code>y1=beta0+beta1.X1+beta2.X2+.....
y2=beta0+beta1.X1+beta2.X2+.....
</code></pre>
<p>Would that be multiple testing scenario? If so, how can be adjusted for it?</p> | g13217 | [
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<p>I am developing a linear model of yield against time (33 years of yield data) where year is 1975,1976....2007. I want to know whether change in yield over time was linear or not. So I fitted a linear model of yield against year:</p>
<pre><code> mdl<-lm(yld ~ year,data=data)
</code></pre>
<p>In my second model, ... | g13218 | [
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<p>I am confused with multiple comparisons adjustments. I have a $p$-values with lot of ones ( due to many scores in foreground are 0) from a fisher-exact test. I get some $p$-values which are significant without multiple testing correction. The $p$-value compose of 1000 $p$-values of </p>
<pre><code> Min. 1st Qu. ... | g58231 | [
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<p>I'm fitting a HMM to time series, for each data set I use BIC results to select the optimum number of states. In that, the BIC number is lowest and thereby indicating this model with that number of states best describes that data set. Is this procedure correct?</p>
<p>For my time series sets (around 500 time serie... | g58232 | [
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<p>Lets say I'm creating a study that looked at treatments for metastasis in African American colon cancer patients. Would my control group or comparison group be Caucasian colon cancer patients with metastasis? I'm a bit confused about how to create control groups in this context. </p> | g58233 | [
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<p>If I have two continuous distributions $f(x)$ and $g(x)$, there are several mathematical ways to combine $f$ and $g$ to get new distributions. Which correspond to what statistical interpretation? For example, if I multiply $f$ and $g$ into $fg$, does $fg$ have a statistical meaning? What about $f/g$, $f \circ g$ and... | g13220 | [
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<p>It seems that there are far more discriminative learning approaches out there than generative. Have discriminative models been studied more in literature than generative?</p>
<p>Thanks</p> | g58234 | [
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<p>The data we are interpolating is monotonically increasing (for example, a car's odometer reading). We have two types of points we'd like the solution to interpolate through. The solution surface must pass through critical points. The solution does not have to pass through non-critical points, but must aim to minimiz... | g58235 | [
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<p>I've 12 unique subjects, and in total I've almost 1700 observations.</p>
<p>I've an ordinal response variable (has 4 levels) and 3 categorical covariates (each one has different levels 3, 5, 2, and 4 respectively).</p>
<p>The values of response and covariates are changing for any unique subject.</p>
<p>What's the... | g58236 | [
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<p>While I was writing up the analysis in my thesis, I just came across when rechecking my test for normality, that the p-value for most continuous variables was .000, which is less than .05, and it rejects the null hypothesis which means to my understanding my data is not normally distributed.</p>
<p>I have already c... | g58237 | [
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<p>For the life of me I cannot find a way to solve this question. Any help would be appreciated!</p>
<p>From past experience, a professor knows that the test score of students taking a final examination is a random variable with mean 65. Suppose in addition the professor knows that the variance of a student's test sco... | g58238 | [
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<p>I have some data about users from different regions visiting different directories of some website. Aggregating that data I get the co-occurrence frequency matrix (for regions and directories). Now I want to distinguish two situations:</p>
<ol>
<li>The users visit directories independently from their regions</li>
<... | g58239 | [
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<p>So, I have a question for a proposal and I'm fairly certain I'm getting an incorrect answer from our local "stats guy". For the record, it's archival data so I can't change the items (which aren't that well done):</p>
<p>One set of items is looking at the appropriateness of behaviour of two types of professionals ... | g58240 | [
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<p>In my clustering problem I'm working with custom similarity measure and looking for any implementation of algorithms with asymmetrical distance or similarity matrix. I'm only interested in those that can offer custom similarity/distance matrix as input or a custom similarity measure function. Language of implementat... | g42104 | [
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<p>For a series of observations $(\vec{x}_i, y_i), i = 1 \cdots N$ from the linear model $Y = \beta^T X + \epsilon$, the least squares estimate of $\beta$ is: $\hat{\beta} = (\mathbf{X}^T \mathbf{X})^{-1}(\mathbf{X}^T\mathbf{Y})$. Fitted values can be obtained as $\hat{y}_i = \hat{\beta}^Tx_i$. However I would like th... | g58241 | [
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<p>In testing the parallel regression assumption in ordinal logistic regression I find there are several approaches. I've used both the graphical approach (as detailed in Harrell´s book) and the approach detailed using the <a href="http://cran.r-project.org/web/packages/ordinal/vignettes/clm_tutorial.pdf" rel="nofollo... | g58242 | [
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<p>I read some articles where theory of rough sets is also considered as data mining algorithm. Hovewer, I have not found so far any example when this theory may be useful in solving data mining problems. I am also wondering that there is no R package for rough sets manipulation.</p>
<p>Could you give me some examples... | g39533 | [
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<p>Imagine two experiments:</p>
<p>1) A group of $n=100$ individuals are under condition $A$, and they perform some test. Among these individuals, $y=5$ individuals succeed in the test. </p>
<p>2) A group of $m=1000$ individuals are under condition $\Delta$ and they perform some test with two possible issues: the fir... | g58243 | [
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<p>I'm using R.After getting an error asking me to provide starting values for a glm (poisson family), I took a look at my data and realized I had quite a bit of zeroes. So, I tried zeroinfl from pscl. I got the "computationally singular" error, so I tried dist="negbin". Same error. I looked at my data via with(bytype,... | g3032 | [
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<p>I calculate multiple linear regression in R with </p>
<pre><code>lm(var ~ VAR1+VAR2+VAR3+VAR4)
</code></pre>
<p>Do you know how to calculate R-squared change for each variable <code>VAR1</code>, <code>VAR2</code>, <code>VAR3</code> ?
Thank you</p> | g13228 | [
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<p>In <a href="http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2441782/" rel="nofollow">this paper</a>, the authors present a scoring algorithm for potential transcription factor binding sites, based on the position-specific probability matrix (PSPM) for that particular transcription factor. </p>
<p>The binding site is 2... | g58244 | [
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<p>Can a gaussian ARMA process have non-gaussian innovations? (i.e., is there an ARMA process that is gaussian, but the corresponding innovations are not gaussian)?</p> | g58245 | [
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<p>I have a nonlinear physical model for which I'm trying to determine parameter uncertainties using Monte Carlo. Instead of describing the nitty-gritty details, I will use a series of figures: </p>
<p><img src="http://i.stack.imgur.com/0unTV.jpg" alt="enter image description here"></p>
<p><img src="http://i.stack.i... | g58246 | [
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<p>What are the lesser known but powerful probabilistic inference algorithms?</p>
<p>Most references about probabilistic graphical models describe popular inference methods like Variable Elimination and Junction Tree. But I think that there are a huge number of other important probabilistic inference algorithms out th... | g58247 | [
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<p>I'm working with a dataset that contains information about consumption of apples. The dataset contains the amount of apple consumed in g/day. The problem with this is that the data points fall into 3 categories:
- a real number (e.g. 54 g/day, people weighing their consumption)
- a discrete number (number of apples... | g58248 | [
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<p>In a mixed model analysis (lme4 + lmerTest for R), I want to analyse the effect of 3 predictors, say <code>A</code>, <code>B</code> and <code>C</code>. Since it is a mixed model, there are two random effects <code>Ran1</code> and <code>Ran2</code>.</p>
<p>I first built a random intercept model with <code>Ran1</code... | g18715 | [
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0.04531747102737427,
0.015382825396955013,
0.0273... |
<p>How I can combine hazards regression coefficient in meta analysis? I want to have a complete regression from combing hazard regression with different covariates. I mean some of them have additional covariates compared to others.</p> | g58249 | [
-0.005753688979893923,
-0.02441374771296978,
0.009879195131361485,
-0.032870352268218994,
0.051312465220689774,
0.009188399650156498,
0.006813898216933012,
0.0009619681513868272,
0.04694344103336334,
-0.03503231704235077,
-0.008354631252586842,
-0.009581065736711025,
0.060303863137960434,
... |
<p>I'm doing different regression tasks based on models of the form
$y=m(x)+\epsilon$ where $y$ is vector valued data, $m(x)$ is the output of a computer model and $\epsilon \sim N(0,V)$ is a multinormal distributed error term.</p>
<p>I assume that the errors are non-correlated so $V$ is a diagonal-matrix which can be... | g13233 | [
0.02527439221739769,
-0.05556275695562363,
-0.023837922140955925,
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0.002165629528462887,
0.042891960591077805,
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0.0007630853797309101,
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0.015220731496810913,
0.007232750300318003,
0... |
<p>I am working with a multivariate time series and using VAR (Vector Autoregression) model for forecasting. My question is What does stationarity actually means in a multivariate framework. </p>
<p>1) I know that if in VAR setup if determinant of inverse of |I-A|matrix has eigen values less than 1 in modulus , the ov... | g58250 | [
0.004634559620171785,
-0.06987162679433823,
0.0006344256107695401,
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0.02065613679587841,
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0.05902932956814766,
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0.01477468479424715,
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0.014513595961034298,
0.03582039102911949,
0.01... |
<p>I'm not a statistician, so I would appreciate an answer in the simplest possible words.
I've read that, in some sense, when we minimize the mean square error, we are maximizing the likelihood.</p>
<p>This seems to have more sense if we consider the noise in the system as pure additive Gaussian noise (i.e. $y = f + ... | g58251 | [
0.051757361739873886,
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0.02493821643292904,
0.0189776923507452,
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0.02217452973127365,
0.10096193104982376,
0.043... |
<p>I am currently assessing whether or not a location-shift can be assumed in non-parametric comparisons to be able to formulate the rejection of the null hypothesis in other terms than the probabilistic index. To do so, I center my data and execute a pairwise two-sample Kolmogorov-Smirnov test on each pair. The data i... | g58252 | [
-0.019892849028110504,
-0.06424357742071152,
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0.06702334433794022,
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-0.012638199143111706,
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-0.00011751599231502041,
0.01596195250749588,... |
<p>There are functions in R (e.g., <code>PP.test</code> and <code>adf.test</code>) which have null hypothesis of unit-root in the process ($H_0$: there is a unit root). Does this null hypothesis mean "the process is difference stationary"? If yes, what is the order of difference required to make it stationary? </p>
<p... | g27 | [
0.04509748890995979,
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0.08220423758029938,
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0.009717212058603764,
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0.0617411769926548,
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<p>I am currently conducting an experiment for part of my coursework as an undergraduate psychology student. I have designed an experiment about naturalistic schemata existing within the individual. I am using basic dichotomous relationships, such as student/teacher and child/parent as examples of natural schemata. Par... | g58253 | [
-0.018352428451180458,
-0.020119108259677887,
-0.007086405996233225,
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0.0374593660235405,
0.009373161010444164,
0.043788932263851166,
0.0... |
<p><em>Dataset of frequent 3-itemsets before running the algorithm:</em></p>
<pre><code>{1, 2, 3}, {1, 2, 4}, {1, 2, 5}, {1, 2, 6}, {1, 3, 4}, {1, 3, 5},
{1, 3, 6}, {2, 3, 4}, {2, 3, 6}, {2, 3, 5}, {3, 4, 5}, {3, 4,6}, {4, 5, 6}.
</code></pre>
<p>Assuming there are only six items in the data set. </p>
<p><strong>Wh... | g58254 | [
0.0012956393184140325,
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0.011106903664767742,
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0.03660454601049423,
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0.008557719178497791,
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0.02269085869193077,
0.004110252484679222,
... |
<p>I have some data which I wish to estimate the marginal distribution of. I have no
real idea what parametric distribution would be suitable, so was planning on fitting a non-parametric (probably kernel) density estimate to the data.</p>
<p>However, there are two complications</p>
<p>1) The data has a hard threshold... | g58255 | [
0.016161857172846794,
0.013683226890861988,
-0.005304494872689247,
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-0.010676789097487926,
0.03275357559323311,
-0.03123496286571026,
0.05431739240884781,
-0... |
<p>To reduce the load on the machine I want to take the benefit of the undersampling approach. Here are a few facts about my data:</p>
<ol>
<li><p>My data is of the order of 20 millions or even more. </p></li>
<li><p>The event rate is around 0.8%.</p></li>
</ol>
<p>Using the undersampling approach, I want to reduce t... | g13236 | [
-0.005086355376988649,
-0.04068400338292122,
0.007289593573659658,
-0.0790041834115982,
-0.02555684559047222,
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0.027433741837739944,
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-0.04793964698910713,
-0.004604677204042673,
0.0033325066324323416,
0.02854314260184765,
... |
<p>Assume I observe a poisson-process with a rate $\boldsymbol{\lambda}$.</p>
<p>I would like to model $\boldsymbol{\lambda}$ as:</p>
<p>$\boldsymbol{\lambda} = \boldsymbol{\pi}_1\boldsymbol{\lambda}_1 + \boldsymbol{\pi}_2\boldsymbol{\lambda}_2$</p>
<p>where</p>
<p>$\boldsymbol{\pi}_k = \text{exp}(\boldsymbol{1}\be... | g58256 | [
0.02598622813820839,
-0.03380013257265091,
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0.08770780265331268,
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0.019792577251791954,
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0.05468406900763512,
-0.0460820347070694,
0.027455193921923637,
0.01346614770591259,
0.05... |
<p>I'm after model that would spit out weights where the weights <code>sum to 1</code> rather than parameters themselves.</p>
<p>This is what I have done:</p>
<p>I have fitted 3 logit models each with 3 independent variables (and <code>y</code> dependent)</p>
<pre><code>logit(y~x+o+z)
logit(y~r+q+a)
logit(y~b+n+m)
<... | g13241 | [
0.02450661174952984,
-0.025023747235536575,
-0.027786577120423317,
-0.04552142322063446,
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0.022728227078914642,
0.007623797282576561,
-0.02466440014541149,
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0.0023109347093850374,
-0.015334559604525566,
0.0007444233051501215,
0.065959133207798,
-0.0... |
<p>A first-order autoregressive process, $X_0,\dots,X_n$, is given through the following conditional distributions:
$X_i | X_{i-1},\dots,X_0 \sim \mathcal{N}(\alpha X_{i-1},1)$,
for $i = 1,2,\dots,n$ and $X_0 \sim \mathcal{N}(0,1)$.</p>
<p>I know that the log-likelihood function $\ell{(\alpha)}$ is of the form:
$\ell(... | g58257 | [
0.02232184447348118,
-0.00030101457377895713,
-0.035286009311676025,
-0.022959640249609947,
0.017607243731617928,
-0.01564186066389084,
0.042842522263526917,
0.015321731567382812,
-0.01910177804529667,
0.006234989035874605,
-0.050172749906778336,
0.0551762580871582,
0.08342703431844711,
0.... |
<p>I am reading over some process analysis data for some failure analysis tests, and I have come across the following definition of an "estimated cumulative probability":
$$F(t) = \frac{i-3/8}{N+1/4},$$
where $i$ is the rank of the failure case (i.e. failure order), and $N$ is the total number of samples.</p>
<p>I had... | g58258 | [
0.03624231368303299,
-0.04419941082596779,
-0.002340752398595214,
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-0.0301186665892601,
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0.09616795182228088,
-0.0072458600625395775,
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-0.016755275428295135,
0.014150923117995262,
-0.017653975635766983,
0.03598965331912041,
0.... |
<p>I need to be able to automatically divide a dataset into two clusters. There are heuristic reasons to expect the data to have two clusters which would be visually clear if one were to plot the data and in cases I have tested this has panned out. I am familiar with otsu's method for turning a grayscale image into a b... | g58259 | [
-0.007812047377228737,
-0.017894839867949486,
-0.004110525827854872,
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0.008586304262280464,
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0.00444729533046484,
0.04654539003968239,
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-0.019701842218637466,
0.06772910058498383,
0.02334270440042019,
0.07938382029533386,
0.0... |
<p>I did not see that explicitly mentioned, even though I think it is correct.</p>
<p>Isn't the exchangeability assumption the most common assumption about examples in the Bayesian setting?</p>
<p>I am thinking of a model of the form $p(x_1,\ldots,x_n,\theta) = p(\theta) \prod_{i=1}^n p(x_i \mid \theta)$, where $p(\t... | g58260 | [
0.018754320219159126,
0.05795206129550934,
0.02105829305946827,
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0.010129592381417751,
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0.01202904712408781,
-0.0074046398513019085,
-0.021566182374954224,
0.05024418607354164,
-0.00221355352550745,
0.01116989180445671,
-0.008856034837663174,
0.0... |
<p>I'm hoping someone can provide an intuitive overview of what quasibinomial is and what it does. I'm particularly interested in these points:</p>
<ol>
<li><p>How quasibinomial differs to the binomial distribution</p></li>
<li><p>When the response variable is a proportion (example values include 0.23, 0.11, 078, 0.98... | g2228 | [
0.020001281052827835,
0.030362071469426155,
0.01724361442029476,
0.008089229464530945,
0.044193118810653687,
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0.03519398719072342,
0.0044422876089811325,
0.0014508083695545793,
0.002821909496560693,
-0.009985726326704025,
-0.009831679984927177,
0.006326968315988779,
0.... |
<p>I have two variables and I need to test if they exhibit a linear relationship so that I will be able to predict a response. Kindly assist in how to handle this problem. This is the data:task is to show that there is linear relationship between bricks used and wastes generated.</p>
<pre><code>Trials 1 ... | g13248 | [
0.03767607733607292,
-0.030243249610066414,
0.01854759268462658,
-0.05916248634457588,
-0.012030472978949547,
-0.07319039851427078,
0.06688561290502548,
-0.0026577257085591555,
-0.008699619211256504,
-0.01898510567843914,
-0.017789948731660843,
0.04011361673474312,
-0.04340566322207451,
0.... |
<p>I am new to meta analysis and how I understood the terminology is that there are actually two ways of performing a meta analysis. Let's consider 5 clinical studies with fixed effects. Fixed effects in terms of the same medical treatment as well as demographic details of the participants. One way of analysing these d... | g58261 | [
0.022290226072072983,
-0.004786318633705378,
0.014267733320593834,
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0.0012592952698469162,
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0.03374486416578293,
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-0.028433460742235184,
0.01057933084666729,
-0.014539900235831738,
0.03336690738797188,
... |
<p>Can you explain intuitively what is a difference between real and imaginary components of Gabor Filter?</p>
<p>Thanks.</p> | g58262 | [
-0.016488092020154,
-0.030098214745521545,
0.01606157049536705,
-0.03114442341029644,
0.03228233382105827,
0.02526078000664711,
0.036079999059438705,
0.060768526047468185,
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0.03078439272940159,
-0.007980088703334332,
0.01714257150888443,
0.020162971690297127,
-0.04055... |
<p>I have a dataset composed of about 36000 attributes and 550 samples, the dataset is generated from text communication between people in some chatrooms.</p>
<p>The questions is when I try to classify these samples, a Naive Bayes classifier always outperforms a support vector machine, both in speed and accuracy. But ... | g58263 | [
0.08383071422576904,
-0.04337095469236374,
0.010794976726174355,
0.024511301890015602,
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0.039831116795539856,
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0.03683556988835335,
0.06845211982727051,
0.0005134974489919841,
0.04654182866215706,
0.0114... |
<p>I have come across the term <em>exponential family</em>. </p>
<p>The Bernoulli, Gaussian and many more distributions come under this exponential family. </p>
<p>What would be the commonalities between them?</p> | g3039 | [
0.04091929271817207,
-0.002681126119568944,
-0.02848006784915924,
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0.010896583087742329,
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0.03237931802868843,
-0.008536029607057571,
-0.05187999829649925,
0.01337750256061554,
0.08407747745513916,
0.04... |
<p>I'm studying the correlation between 2 continuous variables (A~B), the first is an independent measured variable (A), the second one is a dependent estimated variable (B). I'd like to know
i) if the correlation (A~B) is statistically different between factor (sites) and
ii) how to group factors with the same correl... | g58264 | [
0.01539005246013403,
-0.05520472675561905,
0.000009099830094783101,
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0.006407817825675011,
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0.053964223712682724,
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-0.019299501553177834,
0.01343804132193327,
0.032588712871074677,
0.0276653952896595,
-0.... |
<p>I am trying to prove that the best minimum mean squared predictor of $r_{t+l}$ for a stationary ARMA model is the conditional mean $E[r_{t+l}|r_t,r_{t-1},...]$</p>
<p>Attempt:
$$r_t = \psi(B)a_t = a_t \psi_1 a_{t-1} +\psi_2a_{t-2}+...$$
thus,
$$r_{t+l} = \sum^\infty_{j=0} \psi_j a_{t+l-j}$$
Let the minimum mean squ... | g58265 | [
0.02194170095026493,
-0.07143551111221313,
-0.011326516047120094,
-0.017069702968001366,
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0.024248801171779633,
0.00021677611221093684,
-0.039881184697151184,
0.004694572649896145,
0.05593756586313248,
0.04230796545743942,
0.06642352789640427,
0.... |
<p>I have a list of m x n similarity score matrix, something like </p>
<pre><code> c1 c2 c3 c4 c5
d1 0.2159824 0.3528572 0.2390016 0.3673485 0.2849448
d2 0.2849448 0.2669695 0.2441495 0.3829949 0.3511353
d3 0.3281100 0.3251407 0.4328260 0.2895... | g13254 | [
-0.01764628477394581,
-0.02437344752252102,
0.008702604100108147,
0.0023109891917556524,
0.03601695969700813,
-0.008446024730801582,
0.01599648781120777,
0.006127637345343828,
-0.05621202290058136,
-0.003277076641097665,
0.004961722996085882,
0.00976481568068266,
0.01202379260212183,
-0.00... |
<p>While studying the standard multivariate linear regression model, I came across the following:</p>
<p><img src="http://i.stack.imgur.com/rQzKp.jpg" alt="enter image description here"></p>
<p>Could anyone please explain me why the last equality holds, and, why $Z(Z'Z)^{-1}Z'$ cannot simply be simplified to $I$ (isn... | g58266 | [
-0.006838521454483271,
0.016868500038981438,
-0.02615327201783657,
0.029943665489554405,
0.04394619166851044,
-0.026435501873493195,
0.0655958354473114,
0.021401189267635345,
-0.027860013768076897,
-0.0007484372472390532,
-0.02890883758664131,
0.07137396931648254,
-0.0013829158851876855,
0... |
<p><img src="http://i.stack.imgur.com/slmXM.png" alt="enter image description here"></p>
<p>Info:</p>
<p><em>Blue line is the official inflation statistics by US Bureau of Labour Stats<br>
Red line is by independent researchers who claim to have created better way to measure inflation<br><br>
Blue line has been sampl... | g13256 | [
-0.03892703726887703,
-0.01484629139304161,
0.0007852471899241209,
0.02973913587629795,
0.007276610471308231,
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-0.00014853656466584653,
0.010100488550961018,
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-0.029984496533870697,
0.013694072142243385,
0.026783550158143044,
0.07178468257188797,
0... |
<p>I've a list of distance (between a genomic feature and the closest gene) and I want to check if these distances are enriched (so if the distance is smaller than raking random distances). My idea was to generate random position and to compute the distance between these random positions and closest gene, and to compa... | g58267 | [
0.0031124844681471586,
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0.0010745342588052154,
0.01019455585628748,
-0.004914481658488512,
0.030933808535337448,
-... |
<p>I'm trying to fit the data in this message (daily temperatures) using the Holt–Winters technique in R, but can't get the seasonal example in <a href="http://a-little-book-of-r-for-time-series.readthedocs.org/en/latest/src/timeseries.html" rel="nofollow">here</a> to work. Is this not possible with these data, or am I... | g58268 | [
0.0015404095174744725,
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0.017552921548485756,
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0.028474392369389534,
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0.10694513469934464,
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-0.01645473763346672,
0.0009767907904461026,
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0.04688599705696106,
-0... |
<p>Yes, I have checked that previous answers to "Ran out of iterations..." questions do not solve my problem.</p>
<p>I have fault data on Firefox, 899 faults and 1395 (estimated) censored faults. The censoring all happens on one of half a dozen start days and half a dozen end days (the initial/final release of a vers... | g13260 | [
0.01976173184812069,
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0.01655096933245659,
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0.05112679675221443,
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0.05709525942802429,
0.1... |
<h1>Background on bias correction constants</h1>
<p>The standard deviation is calculated like this:</p>
<p>$$
SD = \left(\frac{1}{N-constant} \sum_{i=1}^N (x_i - \overline{x})^2\right)^{1/2}
$$</p>
<p>Following <a href="http://en.wikipedia.org/wiki/Standard_deviation#Estimation" rel="nofollow">Wikipedia's entry on t... | g58269 | [
0.0360044501721859,
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0.005260207690298557,
0.04240518435835838,
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0.018991075456142426,
0.05927518010139465,
0.052646126598119736,
0.01485477201640606,
-0.0008... |
<p>Regression forests are basically random forests, however used for regression. They basically use the same framework as decision forests use for classification with a few parts exchanged.</p>
<p>Two of these parts are:</p>
<ol>
<li>How to calculate the information gain when deciding how to split at a node?</li>
<li... | g13262 | [
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0.0421772263944149,
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-0.0032332506962120533,
0.07831379771232605,
-0.... |
<p>Info about dataset: 5 classes, 200 trials, 100 features.</p>
<p>(I know about the trial to feature ratio being very low, but can not avoid this here and still got well enough classification results.)</p>
<p>Within a ten-fold cross-validation a SVM classifier was trained for each fold (linear nu-svm, optimal nu was... | g13263 | [
-0.046563927084207535,
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0.02120894566178322,
0.013513718731701374,
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0.031386230140924454,
0.070... |
<p>I am running a Monte Carlo simulation, using the results of a GAM (response) as the basis for my overall model. I would like to incorporate the error in the GAM into the final result. Since predict.gam (mgcv) includes se.fit, is there a way to resample the response around this standard error? I was thinking of usi... | g58270 | [
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0.03538031876087189,
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... |
<p>I have a two-sample t-test where the t-statistic is equal to the critical t-value (at three decimal points) at a p-value of 0.05. does this mean i reject the null hypothesis or the opposite? thank you so much!</p> | g49525 | [
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0.034309353679418564,
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<p>For a probabilistic multi-class classifier we can get probabilities of membership of a new point $x$ to each class $y_i$; in case of 3 classes suppose that we get $P(y_a|x) > P(y_b|x) > P(y_c|x)$, thus the most probable class of x is $y_a$. Now suppose that we have a multi-class svm where we can get scores of ... | g13265 | [
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0.05968102440237999,
0... |
<p>Say I have a very large sample of observations, like a thousand of them, and I want to do (multiple) linear regression on them, i.e., regressing the response variable on the predictors. Now instead of doing so, I would randomly sample a subset of that large sample (say half of it, or a third of it, or even a fourth)... | g58271 | [
-0.003057433059439063,
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0.0029762722551822662,
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-0.01906340755522251,
0.010957038030028343,
-0.004743424244225025,
0.024476412683725357,... |
<p>I got the following exercise where i have to understand the steps theres are done:</p>
<p>Since $z_T \sim N(0,T)$:</p>
<p>$$\text{Prob}((\mu-0.5\sigma^2)T+\sigma z_T>rT)$$
$$\text{Prob}(z_T>-\dfrac{(\mu-r-0.5\sigma^2)T}{\sigma})$$
$$\text{Prob}(z_T<\dfrac{(\mu-r-0.5\sigma^2)T}{\sigma})$$</p>
<p>Then i do... | g58272 | [
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0.007900468073785305,
-0.029828425496816635,
-0.004813698586076498,
0.05584792047739029,
-0.058101970702409744,
0.08014114946126938,
0.009410277009010315,
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-0.009856929071247578,
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0.04466467723250389,
0.0063564530573785305,
-... |
<p>I need to implement an RF created by R on Hadoop. I know a way is to recreate the random forest with the same training data using Mahout. But is it possible to convert the RF created by R directly into a format that Mahout can use, for scoring?</p> | g13267 | [
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0.0... |
<p><strong>Contex</strong></p>
<p>Multiple regression with continuous variables. </p>
<p>Conventional statistical packages, e.g. SPSS, lm() in R, typically give me an <em>F</em> value, dfs, and a significance test on whether the model is performing well. I can also use ANOVA to compare whether one model is signific... | g58273 | [
0.05764001980423927,
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0.030734864994883537,
0.00654588034376502,
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0.03305046260356903,
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-0.037528689950704575,
0.03512709587812424,
-0.05055464431643486,
0.07460043579339981,
0.02... |
<p>Is it possible to detect a periodic pattern in a time series using discrete Wavelet Transform?</p>
<p>Is there any package in R to do this job?</p> | g58274 | [
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0.010024203918874264,
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-0.02919837087392807,
0.003352930536493659,
0.02486145682632923,
0.014177700504660606,
0... |
<p>I have ad campaigns that I want to display to users. Each one has criteria a user must meet in order for them to be valid for the campaign. For example, "User must be in the USA", or "User must like the albums by at least one of the artists [The Beatles, Michael Jackson], AND user must be in USA". </p>
<p>Right now... | g58275 | [
-0.05293353274464607,
0.02290235087275505,
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-0.007154680788516998,
-0.02104903571307659,
0.05160493403673172,
0.015763305127620697,
0.036017317324876785,
-0.016538547351956367,
0.01755501888692379,
0.02041221596300602,
0.09137890487909317,
-0.01... |
<p>Does anyone know a good method to determine if clustering using kmeans is even appropriate? That is, what if your sample is actually homogenous? I know something like a mixture model (via mclust in R) will provide fit statistics for the 1:k cluster case, but it seems like all of the techniques to evaluate kmeans req... | g13272 | [
0.0023778306785970926,
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0.014689887873828411,
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0.0002576362749096006,
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-0.01979963481426239,
0.038868874311447144,
0.0047437106259167194,
0.011635192669928074,
0.05584884062409401,
-0.023764530196785927,
0.057899098843336105,
... |
<p>Suppose that when making a histogram, one encounters a datum at a bin boundary. Is there a convention on how to round it? For example, suppose my data are integer percentages, running from 0% to 100%. I want to make a histogram with boundaries at 10%, 20%, etc. Of course I could label the histogram in a way to a... | g13273 | [
0.0031825557816773653,
0.02368277497589588,
0.003926970064640045,
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0.02598549984395504,
0.004503604490309954,
0.026847096160054207,
0.006530385930091143,
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-0.050650618970394135,
0.032707031816244125,
0.04248727113008499,
0.06402122229337692,
0.0047... |
<p>I am trying to fit a time series model to the following data. It seems to be seasonal. Would an ARIMA model be good?</p>
<p><img src="http://i.stack.imgur.com/7LaZu.jpg" alt="enter image description here">
Here is the data:</p>
<pre><code>Count
</code></pre>
<p>2
1
4
5
4
8
7
11
4
4
11
7
10
7
0
19
13
13
11
9
8
16
... | g46454 | [
0.042531415820121765,
0.009702278301119804,
0.02167554199695587,
-0.04380056634545326,
-0.049361418932676315,
0.02995765581727028,
0.04513586312532425,
-0.01616501808166504,
-0.030141806229948997,
-0.008930820971727371,
0.040100667625665665,
0.0016751051880419254,
0.07603956013917923,
-0.0... |
<p>I found this preprocessor where they had the data log transformed with $log_{10}(100+data)$. I am not sure what this log transformation exactly does. Any suggestions?</p> | g47294 | [
0.009310012683272362,
0.032596394419670105,
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0.011678076349198818,
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-0.08680083602666855,
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0.031354013830423355,
0.060105402022600174,
-0.0... |
<p>I have a random forest regression model with 1000 trees, having 16 parameters (using python scikit-learn). The estimator can predict a target value with cross validated r2 score of 0.87 +/- 0.03.
I would like to find the global (or at least close to global) maximum of the random forest, in order to identify the best... | g13275 | [
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0.05428708717226982,
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0.0038502232637256384,
0.013301276601850986,
-... |
<p>I used nlm function in R to do the optimization. When I calculated the correlation between estimated parameters using the inverse of Hessian matrix, I got negative values on the diagonal. My questions are what could be the reason for that issue, and what could be possible solution?</p> | g58276 | [
0.04158351197838783,
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0.024276720359921455,
0.03070191666483879,
0.... |
<p>I have just started reading about Latent Dirichlet Allocation LDA and want to apply it to my project.</p>
<p>May I know if LDA is able to assign a topic to more than one word?</p>
<p>For example, Article A talks about "river banks" while Article B talks about "The role of banks in finance". Hence, will LDA allow t... | g58277 | [
0.024969831109046936,
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<p>We are attempting to create a US heatmap using only zipcode and corresponding values using R. While there are a number of examples that use lat and long data for creating such maps, is there one that will accept zipcodes and colour the corresponding regions on a map ? Preferably using some package that will produce ... | g58278 | [
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0.06775860488414764,
0.020939452573657036,
0.11176963895559311,
0... |
<p>I am ust a little bit confused about whether I should use a scatter plot or a 2D histogram to fit a mixture of Gaussians.</p>
<p>The problem is I have intensities from one image with 2 channels. For example, a RGB image but using just Red and Green channels. Then I plot the scatter plot and try to do a mixture of G... | g13279 | [
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0.07078485935926437,
0.022368622943758965,
0.024758033454418182,
-0... |
<p>The general problem is that I have an calculated variable that represents agreement across parts. The variable is a summation in the form (part/count of parts)^2 for possible parts. The summation variable is between 0 and 1. How would I go about testing for significant differences between calculated part agreement f... | g58279 | [
0.004225840792059898,
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0.008332211524248123,
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0.026260487735271454,
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... |
<p>So this is really difficult for me, but I would like to know if this is possible.</p>
<p>Let's assume I have an unfair coin (absolutely no assumptions can be made about the coin), and my past result has been <code>T-T-T-H-T-H-T-T-T</code> and I want to predict the the result of the next toss. In a way that let me f... | g13281 | [
0.019640158861875534,
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0.01987607032060623,
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-0.028427470475435257,
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0.04269339144229889,
0.017864638939499855,
-... |
<p>Following are similar to but different from previous posts <a href="http://stats.stackexchange.com/questions/84216/correspondence-between-moment-generating-functions-and-distributions">here</a> and <a href="http://stats.stackexchange.com/questions/25010/identity-of-moment-generating-functions">here</a></p>
<ol>
<li... | g58280 | [
0.021910514682531357,
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0.011280199512839317,
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0.004931624513119459,
-0.... |
<p>In creating a content-based recommender, I have several binary measurements, combined with integer measurement values and I wish to compare the two vectors.</p>
<p>For example, consider the following two users and traits t1 - t5, where the traits could be, for example:</p>
<ul>
<li>meets_requirement1</li>
<li>meet... | g13284 | [
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0.05193295329809189,
0.02845768816769123,
-0.05... |
<p>I have data in the form of timestamp,lat,long which is gps data for users.
I'm new to data mining and want to understand how can I start clustering these data to understand more about it.</p>
<p>Should I like build a matrix of one trajectory v/s the other based on some distance metric and then apply some clusterin... | g58281 | [
0.06468893587589264,
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0.021535316482186317,
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<p>I am analyzing some time course data in which I have set up a GLM using R for each subject. Each GLM I want to run is an attempt to extract estimates of different behavioral conditions effects on the time series, and each GLM is all within a single individual. </p>
<pre><code>glm(dilation~happy+fear+neutral+post_de... | g13286 | [
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0.010197550989687443,
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0.009496293030679226,
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-0.015223485417664051,
0.020838316529989243,
0.039218977093696594,
-0.008139590732753277,
... |
<p>I would like to generate a random number from a piecewise exponential distribution.
I consider that the time-scale is divided in $J$ intervals with bounds $(s_{j-1},s_j]$, for $j=1,...,J$, and corresponding rates $\lambda_j$.</p>
<p>Considering the memoryless property of the standard exponential distribution, is it... | g13287 | [
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0.017248520627617836,
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0.055062320083379745,... |
<p>I've made several biochemistry experiments, and in which I compare several groups to a control group. I want to compare the results of 8 such experiments, so basically I have 8 measurements in each group, but the measurements in the control group is all 100%. How do I compare them? I.e., I have four groups, the firs... | g58282 | [
0.008977224119007587,
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-0.015980057418346405,
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<p>I have few questions that came up while I was trying to calculate post hoc power analysis for a regression model: </p>
<ol>
<li><p>I calculated post hoc power analysis for a regression model that
produced a statistically significant (adjusted) R2 = .36 [F (2, 433)
= 121.2, p < .001]. N=405. Number of predictors=... | g58283 | [
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0.053577970713377,
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0.... |
<p>I am running a fixed effects regression in Stata: $y=\alpha+\beta D$ (omitting the FE), where $D$ is a dummy variable. Basically, I want the mean of group $D=0$ and of group $D=1$ after controlling for time invariant heterogeneity via fixed effects, along with their standard deviations. Stata reports coefficients an... | g2352 | [
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0.04281255230307579,
0.059621796011924744,
-0.02338293194770813,
-0.02992490492761135,
0.012748225592076778,
0.04806213453412056,
0.03530228137969971,
0... |
<p>Initially things were done in a particular way (A) and I changed to in some key ways to do things a bit differently (B). Now I wish to evaluate whether the change was for the better. What tests can I do to validate this claim? I have historical and observational data for 3 years on each of the approaches. Which stat... | g13289 | [
-0.0020057684741914272,
-0.06328777223825455,
0.0011222229804843664,
0.0039320094510912895,
-0.0030670268461108208,
-0.0063727302476763725,
0.049908347427845,
0.0445246547460556,
-0.005065149161964655,
0.025829825550317764,
0.030995763838291168,
0.03612086549401283,
0.0632767379283905,
0.0... |
<p>I am developing a linear model with 13 variables, including the target variable (online purchase revenue for items). So, I first built model1 with regular variable and then build model2 after normalizing of the data. I have copied the coefficients for two models here :</p>
<pre><code>Model1(Without Normalized Data)... | g42152 | [
-0.015271265991032124,
-0.08011051267385483,
0.007591896690428257,
0.005493548233062029,
0.011307643726468086,
-0.024639904499053955,
0.00905939657241106,
0.0371866300702095,
0.01507185772061348,
-0.016560934484004974,
-0.0057510435581207275,
0.03322790563106537,
0.06674756109714508,
-0.02... |
<p>Although I read <a href="http://stats.stackexchange.com/questions/60500/how-to-find-a-good-fit-for-semi-sinusoidal-model-in-r">this</a> post, I still have no idea how to apply this to my own data and hope that someone can help me out.</p>
<p>I have the following data:</p>
<pre><code>y <- c(11.622967, 12.006081,... | g13292 | [
0.01308127399533987,
-0.050340231508016586,
0.0038907858543097973,
-0.06346084922552109,
0.02787807397544384,
-0.027533549815416336,
0.0719861164689064,
0.011046155355870724,
-0.0048435344360768795,
-0.014166696928441525,
-0.025539221242070198,
0.03636717051267624,
-0.0035788356326520443,
... |
<p>I'm new to text mining and I'm not sure if could be applied here:</p>
<p>I have labeled sentences but the words I work with are codes, so each word length ranges from 5 to 15 letters and there are only 4 different letters (A, B, C, D).</p>
<p>Looks like this :</p>
<pre><code>Sentence1: AAABCD BAAAA ABCCBAA CCCCC.... | g58284 | [
0.006403600797057152,
0.01157162245362997,
-0.013544316403567791,
-0.05711168795824051,
0.044512905180454254,
-0.0858287587761879,
-0.038333069533109665,
-0.00022192519099917263,
-0.06169170141220093,
-0.026835912838578224,
-0.012166698463261127,
0.032895512878894806,
0.02477041259407997,
... |
<p>I have an experiment with bacteria for which I measured growth curves of several bacterial clones in two different types of media (treat). I then extracted several growth parameters from the curves and am analysing one of these: lag phase (lambda). clone has 13 levels and treat has 2 levels. I now want to know, for... | g58285 | [
-0.026172112673521042,
-0.05104605108499527,
0.0048568760976195335,
-0.01878352463245392,
0.0601729080080986,
-0.04029158130288124,
0.021198296919465065,
0.01850355602800846,
-0.037873875349760056,
-0.025460194796323776,
-0.014508469961583614,
0.04969879239797592,
0.04570022597908974,
0.05... |
<p>Take a look at Table 1 on page 268 in <a href="http://www.math.ku.dk/~rolf/teaching/thesis/DixonColes.pdf" rel="nofollow">http://www.math.ku.dk/~rolf/teaching/thesis/DixonColes.pdf</a></p>
<p>It says at the end of the previous page that the standard errors are computed "on the basis of an underlying multinomial mod... | g58286 | [
0.03462439775466919,
-0.04825875908136368,
-0.008968519978225231,
-0.01702040620148182,
0.0034117656759917736,
-0.029023658484220505,
-0.027948860079050064,
0.018802935257554054,
-0.039564214646816254,
0.032431166619062424,
-0.016891131177544594,
-0.003331908490508795,
0.03553914651274681,
... |
<p>I am comparing multiple published equation forms, refit with independent data. I'm trying to be true to the original authors' methods as much as possible. Therefore, I have 3 linear equations (fit in R using lm()), two of which use transformed Y-variables, and one equation fit using nonlinear regression (fit in R u... | g58287 | [
0.006775356363505125,
-0.09491504728794098,
-0.010722297243773937,
-0.007876391522586346,
-0.05230757221579552,
0.010232686065137386,
0.02519999071955681,
0.013663718476891518,
-0.06681802123785019,
-0.0029306369833648205,
0.031064866110682487,
0.055090997368097305,
0.019606713205575943,
-... |
<p>I used MATLAB neural network toolbox to train a self-organizing map for a given data set. The obtained "weight-position" plot is given as follows. I do not think this plot looks good in comparison to the sample plot given in the <a href="http://www.mathworks.com/help/toolbox/nnet/ref/plotsompos.html" rel="nofollow"... | g42158 | [
-0.0008132674847729504,
0.04230141639709473,
-0.0006210432038642466,
-0.02173963375389576,
-0.04036295413970947,
0.0076903607696294785,
0.020091215148568153,
-0.0036658989265561104,
-0.07345890998840332,
-0.00008466982399113476,
0.006224439479410648,
-0.02131500653922558,
0.08338319510221481... |
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