question stringlengths 37 38.8k | group_id stringlengths 2 6 | sentence_embeddings listlengths 768 768 |
|---|---|---|
<h2>Outline</h2>
<p>I'm working with data corrupted by a mixed Poisson-Gaussian noise model (for example with images gathered in astronomy or electron microscopy), and have been using the generalized Anscombe data transformation described in the paper:</p>
<blockquote>
<p>"<em>Optimal inversion of the generalized A... | g60203 | [
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<p>I'm a journalist, and I am trying to work out whether hospitals that are in political districts with low majorities (i.e. where the political representative is fighting hard for his or her seat) are more likely to get extra funding. </p>
<p>In other words, do hospitals that have received extra funding tend to be in... | g45611 | [
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<p>I'm programming a web tool (=<em>"I'm a stats ignoramous who drifted here from stackoverflow.com"</em>) that allows scientists to enter predictions about the 5-number-summary stats for a variable. Entry is done using the UI-metaphor of a box-plot.</p>
<h2>I'd like to allow scientists to visualize their input as a P... | g570 | [
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<p>I have heard the term "orthogonal * validation" used recently. It was used in the context of experimental platform testing. What does this mean? I cannot find anything on it in literature or Wikipedia.</p> | g16184 | [
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<p>I have a given data set $D = \{ x_i, y_i \}_{i=1}^n$ for a <strong>regression problem</strong>. When I plot the data, it looks like there is an <strong>underlying parabola</strong> (2nd
order linear model) and some outliers.</p>
<p>I want to design an approach using a <strong>probabilistic model</strong> with a lat... | g60204 | [
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<p>I have 2 simple questions about linear regression:</p>
<ol>
<li>When is it advised to standardize the explanatory variables?</li>
<li>Once estimation is carried out with standardized values, how can one predict with new values (how one should standardize the new values)? </li>
</ol>
<p>Some references would be hel... | g947 | [
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<p>Here's my understanding so far: To perform PCA, you have to subtract the means of each column from the data, compute the correlation coefficient matrix and then find the eigenvectors and eigenvalues. Well, rather, this is what I did to implement it in Python, except it only works with small matrices because the meth... | g16186 | [
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<p>What is/are the difference(s) between a longitudinal design and a time series?</p> | g16187 | [
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<p>I'm wondering how far along the natural language processing is in determining the semantic distance between two excerpts of text.</p>
<p>For instance, consider the following phrases</p>
<ol>
<li>Early today, I got up and washed my car.</li>
<li>I cleaned my truck up this morning.</li>
<li>Bananas are an excellent ... | g60205 | [
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<p>I have a dataset with which I would like to compare the effect of species and habitat on movement rate, with pairwise comparisons. I would also like to include the effect of individual (as a random factor?) - this random factor is the part I don't know how to do, at least not in the framework of <code>Anova()</code... | g15611 | [
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<p>I'm trying to write my own code for cluster-robust (AKA panel-robust, AKA heteroskedasticity and serial-correlation-consistent) standard errors, so that I can make a couple of small extensions. But I can't get my results to match Stata's (in which this procedure is routine), so I am probably missing some detail. W... | g60206 | [
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<p>I'm novice in time series analysis and completely lost through reading so..
I have an enormous dataset of discrete time series of aggregated events and I wish to fit each one of them into ARIMA models. Therefore I have to ensure that the time series are stationary, which I do through adf and kpss tests. However I wo... | g45623 | [
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<p>I have a probability distribution and I'm trying to extract some information from it. Specifically, I'm trying to determine the mean, variance, and standard deviation.</p>
<p>Am I able to determine those from the distribution table, and if so, how should I approach the problem?</p>
<p>To further clarify on the nat... | g45624 | [
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<p>Let's pretend I'm conducting a poll/survey. It's a simple yes/no poll (i.e. everyone only gives 1 of 2 answers). I have asked N people so far, and X of them have said "yes".</p>
<p>I would like to stop asking people (i.e. stop the poll) when I can be sure to some high level of statistical confidence (e.g. 95% sure)... | g45626 | [
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<p>How to prove that for the radial basis function $k(x, y) = \exp(-\frac{||x-y||^2)}{2\sigma^2})$ there is no finite-dimensional feature space $H$ such that for some $\Phi: \text{R}^n \to H$ we have $k(x, y) = \langle \Phi(x), \Phi(y)\rangle$?</p> | g60207 | [
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<p>I have a ordinary linear regression model like this</p>
<pre><code>y = b0 + b1*x + b2*z + b3*x*z
</code></pre>
<p>I used <code>PROC GLM</code> in <code>SAS</code> to test the model. Now I want to export the variance-covariance matrix of the coefficients (<code>b0</code>, <code>b1</code>, <code>b2</code>, and <code... | g60208 | [
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<p>I have a process that generates a sequence of events, where each event is of a certain type (let's say $A$, $B$, and $C$). The length of each generated sequence is random.</p>
<p>I wish to count the number of events of each type and calculate the probability that an event is of a certain type. For example, for the ... | g60209 | [
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<p>Lets say for two samples, treatment and control, there are three constituent molecules each and their corresponding amounts are as follows:</p>
<pre><code>Tr. Ct.
2 1
5 2
6 3
</code></pre>
<p>I wish to find out the individual ratios for these three constituent molecules. But however if for some reason the ... | g60210 | [
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<p>I've just started to learn to use <a href="http://mc-stan.org/" rel="nofollow">Stan</a> and <code>rstan</code>. Unless I've always been confused about how JAGS/BUGS worked, I thought you always had to define a prior distribution of some kind for every parameter in the model to be drawn from. It appears that you don'... | g16198 | [
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<p>Following this R instruction</p>
<pre><code>> fit <- lm(spending ~ sex + status + income + verbal, data=spending)
</code></pre>
<p>I would like to calculate the mean and median of the residuals. Both my friend and I get different answers for the mean for the same data. </p>
<pre><code>> mean(resid(fit))
... | g60211 | [
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... |
<p>I have two time series <code>q</code> and <code>c</code> and I want to calculate dynamic time wrapping (DTW) distance between these two time series:</p>
<pre><code>q<-c(1,3,4,5,6,7)
c<-c(2,3,1,5,3,4)
</code></pre>
<p>As I understand we should make a matrix like this:</p>
<pre><code>4 | 9 1 0 1 4 9
3 | ... | g60212 | [
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<p>In reading Blake Master's notes on Peter Thiel's lecture on start ups, I came across <a href="http://blakemasters.tumblr.com/post/21169325300/peter-thiels-cs183-startup-class-4-notes-essay">this metaphor</a> of the technology frontier: </p>
<blockquote>
<p>Picture the world as being covered by ponds, lakes, and o... | g60213 | [
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... |
<p><em>Suppose $X_1,X_2,...X_n$ are i. i. d. random variables with p. d. f.
$$f(x)=xe^{-x}I_{(0,\infty)}\!(x)$$
and let $Y_1,...,Y_n$ be the order statistics for these variables.</em></p>
<p><em>a) Find the conditional p. d. f. of $Y_1$ given $Y_n=y_n$.</em></p>
<p>When working with order statistics, one should start... | g16201 | [
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... |
<p>I am quite new to statistics, so please forgive me for using probably the wrong vocabulary.</p>
<p>I have some data that looks (to me) like a gaussian when plotted.</p>
<p>The data is an extract from a jpeg image. It's a vertical line taken from the image, and only the Red data is used (from RGB).</p>
<p>Here is ... | g49584 | [
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-... |
<p>Many authors of papers I read affirm SVMs is superior technique to face their regression/classification problem, aware that they couldn't get similar results through NNs. Often the comparison states that</p>
<p>SVMs, instead of NNs,</p>
<ul>
<li>Have a strong founding theory </li>
<li>Reach the global optimum due ... | g60214 | [
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<p>I will be collecting data from three three different groups. I will be interviewing women (probabilistic sample) and then asking them to provide a name to build the other two groups (convenience sample). I would like to know what is the best approach to analyze all this data?</p>
<p>My study is about: Breastfeeding... | g60215 | [
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0.075... |
<p>I am performing a regression on a large dataset that is fairly noisy. The line I am running in R is:</p>
<pre><code>lmfit <- lm(predictVariable ~ dataSet[,1:10])
</code></pre>
<p>so I have 10 endogenous variables. The results are somewhat strange:</p>
<ol>
<li><p>significant t-statistics for all the coefficien... | g60216 | [
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<p>I am reading <a href="http://www.amazon.co.uk/Modern-Regression-Techniques-Using-Practical/dp/1847879020" rel="nofollow">Modern Regression Techniques Using R</a> (Wright and London, 2011).</p>
<p>At the end of the chapter on "Robust regression", in the summary of "Statistical concepts", there it says, </p>
<blockq... | g60217 | [
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<p>In the setting of multivariate multiple regression (vector regressor and regressand), the four major tests for the general hypothesis (Wilk's Lambda, Pillai-Bartlett, Hotelling-Lawley, and Roy's Largest Root) all depend on the eigenvalues of the matrix $H E^{-1}$, where $H$ and $E$ are the 'explained' and 'total' va... | g45632 | [
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... |
<p>I have a time series that zigzags up and down in cycles. I want to find a simple algorithm to partition it into segments of up sequences and down sequences. </p>
<p>It should be robust to noise so that a small kink shouldn't partition a sequence needlessly. Is there a name for such a technique? </p>
<p><strong>EDI... | g60218 | [
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0.08133090287446976,
-0.01... |
<p>In my statistics lectures it is mentioned that for balanced data (same number of participants in each block), the results will be the same whether the model is fitted with factor A as a fixed effect or a random effect. For example:</p>
<pre><code>lme(effort ~ Type, random = ~1|Subject)
</code></pre>
<p>will give m... | g60219 | [
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... |
<p>I have used mutli-stage sampling (i.e. cluster and stratified sampling) to select four units within a geographical area. Each unit was selected randomly from a list of that unit. There are only four different types of units in the geographical area, so the unit selected is representative of each unit type. (I establ... | g60220 | [
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0.0... |
<p>I generate an AR(1) process as follows:</p>
<pre><code>x=arima.sim(list(order = c(1,0,0),ar=0.67),n=1000,sd=sqrt(0.55))
</code></pre>
<p>When I square it, and fit AR(1) to the squared process, it seems still to be fitted well using AR(1) model:</p>
<pre><code>y=x^2
fit=ar(y,order.max=1, method="ols")
acf(fit$resi... | g37444 | [
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... |
<p>I have some time series data that I want to perform a linear regression on.</p>
<p>Every year a variable number of locations were sampled, I want to find the overall trend in these measurements. However some sites were sampled for two or more years in a row, while some were not. How do I take this into account when... | g60221 | [
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0.032505959272384644... |
<p>I am fitting an ARIMA model on a daily time series.
Data are collected daily from 02-01-2010 to 30-07-2011 and are about newspaper sales.
Since a weekly pattern in sales can be found (the daily average amount of copies sold is usually the same from Monday to Friday, then increases on Saturday and Sunday), I am tryin... | g49388 | [
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<p>This is a problem from capture-mark-recapture study. I specify a model where parameters $c$ and $p$ have equal intercept. In MARK, a design matrix would look like</p>
<p><img src="http://i.stack.imgur.com/GJ0zM.jpg" alt="enter image description here"></p>
<p>and I would name it as $c=p(.)$.</p>
<p>Extending this ... | g19695 | [
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0.041064582765102386,
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0.01633... |
<p>I have what I think is a simple question. </p>
<p>Let say I have 5 data sets with with a variable number of tests (say 1-10K) and I control the FDR in each set to 1% using BH. If I combine these BH adjusted sets into one big set, will the FDR of the big set still be 1%? Each data set was analyzed identically, but ... | g16209 | [
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0.0... |
<p>I often deal with reasonable sized amount of time series data, 50-200 million doubles with associated time stamps and would like to visualize them dynamically.</p>
<p>Is there existing software to do this effectively? How about libraries and data formats? <a href="http://hackage.haskell.org/package/zoom-cache" rel=... | g45643 | [
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<p>I am comparing 4 different tests for the evaluation/identification of cancer. One is a continuous variable yielding cut-off values based on both the mean and the median of 5 consecutive measurements in the same patient. The other 3 tests are nominal tests staging the lesions from 0 (benign) - 4 (1-4 being malignant)... | g60222 | [
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<p>Consider the problem of sampling from $p(\mathbf{x}, \mathbf{y})$ using the Metropolis or Metropolis-Hastings (MH) algorithm. I can either propose samples for $p(\mathbf{x}, \mathbf{y})$ directly, or I could do a blocked version of that and alternately propose samples for $p(\mathbf{x} \mid \mathbf{y})$ and $p(\math... | g60223 | [
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<p>I'm using <strong>sctest</strong> function in strucchange package to check if there are breaks in my series.</p>
<p>I would like to understand how to interpret its result, in an example i get:</p>
<pre><code>> g <- sctest(cars$dist~cars$speed+0)
> g
Recursive CUSUM test
data: cars$dist ~ cars$speed... | g60224 | [
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0.018487604334950447,
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-... |
<p>I have a process under test (approximately normal distributed), and I have calculated <a href="https://en.wikipedia.org/wiki/Process_capability_index" rel="nofollow">$C_{pk}$ (a process capability index)</a> for this process. These values are compared to reference values which are of the same process under some cond... | g7514 | [
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<p>I am solving this problem:
$$
\sum_i \parallel f(x_i)- y_i\parallel_2^2 + \lambda <\psi f, \psi f>_{L_2}^2
$$
where the second part $<\psi f, \psi f>_2^2$ is regularizer using the linear operand in hilbert space $\psi$.
When I model my function $f$ as
$$
f(x)=\sum_k k(x, x_k) \alpha_k
$$
the regressio... | g60225 | [
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0.... |
<p>Let's say that we have longitudinal panel data. Rows are unique by date and individual. Columns consist of characteristics of the individuals on the given date as well as a dependent variable. </p>
<p>My ultimate objective is to perform a cross-sectional regression as well as a panel regression as there appears to ... | g45655 | [
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<p>I generated a list of 35 proven benefits on a subject and asked the public to choose five which would be most likely to influence their behaviour.</p>
<p>43 respondents cast 215 votes, and three of the benefits received many more votes than the others.</p>
<p>What would be the best statistical tool to measure the ... | g60226 | [
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<p>I compared the number of pregnant women receiving specific health service indicators (deliveries, antenatal attendances and malaria prophylaxis uptake) at 14 facilities during three specific time periods; pre, during and after a project intervention; using the pre-intervention data set as the reference in a Poisson ... | g60227 | [
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<p>I'm encountering an issue where a classifier I'm developing reports validation errors during training that span a wide range of values without consistently decreasing over time. Unfortunately, I'm new to ML and related topics and can't seem to diagnose the problem as a result. </p>
<p>The base code of the classifie... | g16221 | [
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<p>The standard error of the intercept term ($\hat{\beta}_0$) in $y=\beta_1x+\beta_0+\varepsilon$ is given by $$SE(\hat{\beta}_0)^2 = \sigma^2\left[\frac{1}{n}+\frac{\bar{x}^2}{\sum_{i=1}^n(x_i-\bar{x})^2}\right]$$
where $\bar{x}$ is the mean of the $x_i$'s.</p>
<p>From what I understand, the SE quantifies your uncert... | g60228 | [
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... |
<p>I flip a coin 20 times and get 14 heads. I want to calculate the p-value of the hypothesis that my coin is fair. What probability should I calculate? In Wikipedia it is written that I need to calculate the probability to get 14 <strong>or more</strong> heads in 20 flips. Why is it 14 "or more"? Why not 14 <strong>or... | g16222 | [
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<p>I have a random events generator. I know in advance the set of event that can be generated (in my case I have only three possible events). The probabilities of the events are not known. I need to estimate these probabilities. For that I run an experiment. For example I generate 20 events. So, I have a sequence of ev... | g45660 | [
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<p>I want to compare which are the "most important" interaction effects (in a data driven way, I realize that it is has downsides). I realize that for substantial researchers this does not make sense, yet am curious to the procedure. </p>
<p>Imagine we have the following variables: $X_1, X_2, X_3, X_4$, $y$ and $z$ (a... | g60229 | [
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<p>Is there a 'limit' function in R? <code>help(lim)</code> or <code>help(limit)</code> weren't useful.</p>
<p>And in general, is R suitable for mathematical computations?</p> | g37665 | [
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<p>Suppose on the flop in no limit hold'em two players go all-in. They both have 2 hole cards and there's 3 community cards on the board at present. There will be 2 more cards drawn and each player will make the best 5 card hand out of the 5 community cards and their own 2 hole cards.</p>
<p>Sometimes people like to "... | g37452 | [
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<p>I have corpora of classified text. From these I create vectors. Each vector corresponds to one document. Vector components are word weights in this document computed as TFIDF values. Next I build a model in which every class is presented by a single vector. Model has as many vectors as there classes in the corpora.... | g19837 | [
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<p>I'm trying to train a randomForest model in R in a 500k+ row dataset. So far so good, but now I'm trying to include factors person_id and company_id (non-unique) which both have a huge amount of levels (in the thousands, many more than R can handle). </p>
<p>There is an overlap between training and test set for the... | g31752 | [
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... |
<p>This questions is two part:</p>
<p>1) What happens when you apply the backshift operator to a constant? For example, if I have the AR process
$$(1-\phi B)(y_t-\mu)=\epsilon_t$$
does that equal
$$y_t-\mu-\phi By_t-\phi B\mu = \epsilon_t$$
which (I believe reduces to)
$$y_t-\mu-\phi y_{t-1}-\phi \mu = \epsilon_t\lo... | g60230 | [
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0.019958598539233208,
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0.03164681792259216,
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0.104435496032238,
-0.03135710582137108,
0.036021... |
<p>Data for certain kinds of variables tends to be non-normal when measured in particular populations (e.g. levels of depression in a population of people with Major Depressive Disorder). Given that Pearson's assumes normality, how robust is the test statistic under conditions of non-normality? </p>
<p>I have a number... | g60231 | [
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<p>I asked a simple survey question and gave 12 options where an individual can choose from 1-12 items. I calculated the frequencies of each item by taking the number of responses to the particular item over the total number of individuals who answer at least one choice. Now if I asked all the respondents what their ge... | g60232 | [
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0.015696320682764053... |
<p>I have a data set with four variables and 3000+ observations on which I performed an LDA. I was wondering how I can use the scaled coefficients of linear discriminants (output of R shown below as example) to draw decision boundaries in the original variable space?</p>
<pre><code> LD1 LD2 LD3
[1,] ... | g60233 | [
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0.00042706175008788705,
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0.024328095838427544,
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-0.02802286110818386,
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0.06552396714687347,
0.05840151384472847,
0... |
<p>I use xtreg, re(random effect model) and there is a message<br>
"The F or chi2 model statistic has been reported as missing. Stata has done that so as to not be misleading, not because there is something necessarily wrong with your model." </p>
<p>I have whole std.err reported and there are no additional problems.... | g60234 | [
0.03805895894765854,
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0.003168505849316716,
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0.02981420047581196,
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-0.03833360970020294,
0.0033542367164045572,
-0.0029906178824603558,
0.03767051547765732,
0.008... |
<p>$X_1$, $X_2$...$X_i$ are independently and identically distributed rvs with distribution of $X_i \sim beta(\alpha,\beta=1)$. Compute the pdf of $Y=\Pi_{i=1}^nX_i$</p>
<p>Is the following solution correct:</p>
<p>pdf of $X_i = f_{X_i}(x_i)$ = $\alpha x^{\alpha -1} , 0\leq x \leq 1$</p>
<p>Starting with cdf of Y:<... | g19854 | [
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<p>I have been thinking of modeling human timing data using <a href="http://mcmc-jags.sourceforge.net/" rel="nofollow">jags</a> where the data comes from an experiment where participants tap in time with a very slow metronome. The data is then a number of measurements of how "off" the tap was compared to the metronome.... | g60235 | [
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<p>I have a medical dataset with approx 200 variables. One of the variables is a bio-marker (concentration of a particular enzyme). It's distribution is right skew, and the problem is that values above a certain level are censored/cut off at that level. So while the mean of the variable is around 10, any values greater... | g16233 | [
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<p>I have a continuous response variable, nominal independent, and want to block by site, though the numbers at sites are unequal. Is there any alternative to a permutation test? If not, does anyone know of an automated process for designing a permutation test for a rookie like me?</p>
<p>Thanks very much</p> | g33919 | [
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<p>I have a dataset of ~ 300 chemical compounds, which are described by ~ 100 independent dummy variables which codify the presence of a particular chemical group (<em>i.e.</em>, these X variables are either 1, if a particular chemical group is present, or 0, in the case that it is not). For these 300 compounds I have ... | g60236 | [
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<p>What statistical analysis test do I need to run? I want to compare type of downloader (Legal and Illegal) to what type of content they download (Music, Movies etc). In SPSS I have set the type of content as a multiple response set because each respondent could choose multiple content. What is the best test to use to... | g16238 | [
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<p>can anyone show me how to find the Fisher information matrix for negative binomial distribution, if I parameterize the Negative Binomial distribution using parameters mean and size. Thank you!</p> | g60237 | [
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<p>I appreciate the usefulness of the bootstrap in obtaining uncertainty estimates, but one thing that's always bothered me about it is that the distribution corresponding to those estimates is the distribution defined by the sample. In general, it seems like a bad idea to believe that our sample frequencies look exact... | g16240 | [
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<p>I am trying to estimate the parameters of the modified Bessel function of the first kind for integer order case. </p>
<p>$I_n(wt) = \sum\limits_{m=0}^\infty \frac{1}{m!(m+n)!}(\frac{wt}{2})^{2m+n}$</p>
<p>In Probability form,</p>
<p>$P(t|w,n) = I_n(wt)*other\_terms$ </p>
<p>and I would like to estimate the param... | g16244 | [
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<p>I have been reading about appropriate measures of central tendency for ordinal level data.
So far I have learned that the median and mode can be used but that the latter can only be used in some cases. Some sources state that the median can only be used with Likert questions when there is an odd number of scores. I... | g45676 | [
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<p>I'm being asked to calculate a necessary sample size for a cluster sampling protocol. I don't have much experience with cluster sampling, so thought I'd come here. The situation is as follows:</p>
<p>1) Clusters: We have two separate groups to run analysis on. One with 75 clusters and one with 150 clusters.</p>
<p... | g60238 | [
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<p>I found this confusing when I use the neural network toolbox in Matlab.<br>
It divided the raw data set into three parts:</p>
<ol>
<li>training set</li>
<li>validation set</li>
<li>test set</li>
</ol>
<p>I notice in many training or learning algorithm, the data is often divided into 2 parts, the training set and t... | g60239 | [
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<p>Are there better alternative methods to choose C and Gamma which yield better training performance?</p> | g45683 | [
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<p>My case is that I have one continuous DV variable and two categorical IVs containing 11 and 12 different levels (YEAR & MONTH) form 1998 to 2008.</p>
<p>Until now I have experimented a lot with contrasts() and the deviation coding seems to be the one I want to use, because I would rather compare the individuals... | g797 | [
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<p>I am new to probability course and find concepts very confusing. I am learning maximum likelihood estimation and as a starting point for that do we find the density or the distribution? </p>
<p>In general, do we find the distribution from density or is it vice versa and how does one find it? For example, for Gaussi... | g60240 | [
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<p>I have one categorical variable that can assume 5 possible values: 1, 2, 3, 4, 5. I observe the value of the variable in two samples of different size. Now I want to compare the frequency distribution of my variable in the two sample.</p>
<p>Is there any statistic that measures the concentration of the distribution... | g60241 | [
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<p>I have a sampling distribution generated by computing the maximum across many samples. I'd now like to generate an estimate for what the true maximum parameter is within the population I sampled from. How can I do this? I thought about the bootstrap, but it didn't work well in estimating the maximum. Can anyone sugg... | g60242 | [
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<p><strong>Entire Population:</strong> 30,000</p>
<p><strong>Known properties of population:</strong> Age, gender, height, weight, </p>
<p><strong>Ideal representative sample size:</strong> ???</p>
<p>This is for a mailing list test group selection. </p>
<p><strong>Problem constraints:</strong></p>
<ol>
<li><p>Cer... | g16256 | [
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<p>For the model given by some independent pairs $(x_i,y_i)$ identically generated from a bivariate Gaussian distribution, there is the convenient semi-conjugate family of "Normal-Wishart" prior distributions. It is mainly convenient because the posterior distributions are easy to simulate, without resorting to MCMC te... | g60243 | [
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<p>Either my intuition is misleading me or my code is wrong. In a nutshell, I have a simple logistic-regression model, and when I look at the posterior distribution of μ, a given unit's probability of succeeding on each trial, I see substantial uncertainty (i.e., variability in the posterior distribution), but when I l... | g60244 | [
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<p>Hopefully this question is not too simple or too general. I am working on a problem right now in which I am given different sets of data. Each data set consists of some number of samples (sampled at irregular points throughout the input space) which consist of a single output value that is associated with a specific... | g16260 | [
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0.016117673367261887,
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0.019938139244914055,
0.016... |
<p>I am very new to regression analysis. I have a dependent variable and 9 independent variables. I want to build the best possible model from them, and I don't know when to log transfrom a variable.</p> | g49325 | [
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... |
<p>I want to model how traffic will flow on real networks (not just the internet, also, say, Intel's internal LAN).</p>
<p>Is there a place I can get real network topologies data I can use?</p> | g9526 | [
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<p>I have data from a psychology experiment in which instructional method was manipulated between subjects via two factors: pretraining (3 levels) and training (2 levels). I assessed participants' performance via two tests, a pretest and a posttest, so I have test accuracy as my dv with test section (pre/post) as a wit... | g16261 | [
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0.... |
<p>I'm running a biological experiment with rodents, have two groups (each consists of 26 animals), where one is treated with a chemical, and one is control (saline).</p>
<p>In one variable, there doesn't seem to be much of a difference between groups. However, when I identify outliers, the data becomes very significa... | g16262 | [
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0.0... |
<p>Trying to plan for upcoming inventory needs for a clothing company.</p>
<p>There is a strong seasonal component to the data. At the beginning of the year, sales are up; at the end, sales are down. </p>
<p>Each year, at the beginning of the year, they acquire more sales people, and so they sell more each year. But!... | g60245 | [
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<p>I have a variable that has both numeric and nominal components. The source has a documentation which helps in identifying which is which and for splitting into their proper components. I will do modeling on these data later on (R or WEKA).</p>
<p>There are several of them and one of it is the <code>size</code> vari... | g60246 | [
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<p>I'm working actually on the modeling of times series with auto.arima from package forecasts. But i enconter some problems regarding the extraction of values Lo 80, Hi 80, Lo 95, Hi 95 singularly. I have retrieved data to excel with function csv but it 's too long and there are some risks to loose data. I have retrie... | g16263 | [
0.0014012529281899333,
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... |
<p>I want to know if a covariate for each subject interacts with three types of trials, and the difficulty of those trials. My dependent measures are accuracy and response times (RT). For this question, I’d like to focus on RTs. Traditionally, people in my field have dichotomized the covariate of interest and used ANOV... | g37662 | [
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0.03515433892607689,
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... |
<p>Does anybody know what type of chart that is? (some sort of bubble chart but with links between bubbles)</p>
<p><a href="http://en.wikipedia.org/wiki/File:PageRanks-Example.svg" rel="nofollow">http://en.wikipedia.org/wiki/File:PageRanks-Example.svg</a>
<img src="http://i.stack.imgur.com/bhjcQ.png" alt="enter image ... | g15620 | [
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0.035607293248176575,
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... |
<p>(Sorry that I've previously formulated the question in a wrong way, which confused everyone including myself. This is a better version of the question. Thanks!)
Here's another order statistics question that I wish to ask.</p>
<p><strong><em>Question</em></strong></p>
<p>Consider $n$ random variables $x_1, x_2,\cdo... | g9529 | [
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0.011606932617723942,
-0.024333929643034935... |
<p>I have a set of values, each of these values has its own mean and variance. I want to be able to account for this variance when I plot the histogram of the means. Something like an error bar on the bins. Is there a commonly used method to this? </p> | g48653 | [
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-0.049072034657001495,
0.02612224966287613,
0.009202380664646626,
0.03494618088006973,
... |
<p>Players of a certain TRPG have characters with 6 ability scores, each ability score ranging from 3-18. One method of generating those is by rolling 4d6 drop lowest. That means four six-faced-dice are rolled, and the three highest results are added. </p>
<p>What's the probability that, given 5 players, one player wi... | g60247 | [
0.011530125513672829,
-0.029071951285004616,
-0.01520590391010046,
-0.03892537206411362,
-0.00993864145129919,
0.0009468959178775549,
0.04404294863343239,
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-0.03033517859876156,
-0.016050299629569054,
-0.05610617250204086,
-0.0055002071894705296,
0.034517135471105576,
... |
<p>In the world of microelectronic design and simulation where the technology gets smaller and smaller (a few nanometers nowadays), the high density and replication of some of our circuits require us to estimate rare event statistics in our design flows. Traditional Monte Carlo cannot be applied as it would take years ... | g9531 | [
0.04660151153802872,
0.0467207245528698,
0.004816505126655102,
0.017204303294420242,
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0.03587549924850464,
0.024700261652469635,
0.012821412645280361,
0.002033289521932602,
0.005472049582749605,
0.041306693106889725,
0.0487336739897728,
-0.00921... |
<p>let X $\sim {\cal N}(\mu,C)$ be a random variable obeying multi-variate normal distribution in $\mathbb{R}^n$ and $U \subset \mathbb{R}^n$ be a vector space with $\dim(U)=n-1$.
What is the probability of X to be at distance ($L_2$) d from U? Assume that d is small (I actually interested in $\lim\limits_{d \rightarro... | g60248 | [
0.01817859709262848,
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0.003951065707951784,
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0.03155158832669258,
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0.05328476428985596,
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-0.... |
<p>My questions are:</p>
<ol>
<li>What are the benefits of kernel trick? Can anyone summarize?</li>
<li><p>One thing I read about in one lecture note is , '<em>we never need to explicitly represent feature vectors</em>'.</p>
<p>I do not quite understand what '<em>explicitly represent</em>' means. Can any one explain?... | g45711 | [
-0.03714684024453163,
0.04218402877449989,
0.020415794104337692,
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0.02773928828537464,
0.05679731443524361,
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-0.01533525437116623,
0.03289977088570595,
0.03526590019464493,
0.07651955634355545,
0.035662... |
<p>I have a time series as following. It has an upward trend and weak sesonality (found in ACF). I tried spectral analysis, but the residual error kept staying over 600, which is not small enough for a prediction. Any advice? Thx!</p>
<pre><code>ts <- c(1530.040 3527.839 3327.613 3613.749 2971.990 3747.925 3352.686... | g60249 | [
0.013526776805520058,
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0.01267295517027378,
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0.06301486492156982,
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0.010172289796173573,
-0.020363887771964073,
0.05577457696199417,
0.07598701119422913,
0.014... |
<p>I have two large (sparse) matrices (500000*500000) and would like to perform the mantel test to get a similarity measure. </p>
<ul>
<li>Is there a way to break-up these matrices into smaller ones and perform the test? </li>
<li>Or can you suggest a way to do it efficiently without running into memory problems? </li... | g45713 | [
-0.013382661156356335,
0.025756509974598885,
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0.0183400958776474,
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0.03476237878203392,
-0.042523909360170364,
-0.00797593966126442,
-0.004888228140771389,
-... |
<h3>Background to Question:</h3>
<p>Previously on Cross Validated, we have had questions on:</p>
<ul>
<li><a href="http://stats.stackexchange.com/questions/396/what-best-practices-should-i-follow-when-preparing-plots">What is best practice when preparing plots?</a></li>
<li><a href="http://stats.stackexchange.com/que... | g16269 | [
0.04452131688594818,
0.012493767775595188,
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0.02390313148498535,
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0.06267175823450089,
0.005414213985204697,
0.019701894372701645,
... |
<p>Final edit with all resources updated:</p>
<p>For a project, I am applying machine learning algorithms for classification.</p>
<p><strong>Challenge:</strong>
Quite limited labeled data and much more unlabeled data.</p>
<p><strong>Goals:</strong></p>
<ol>
<li>Apply semi-supervised classification</li>
<li>Apply a ... | g60250 | [
-0.009368295781314373,
-0.07076038420200348,
0.028175605461001396,
-0.05930482596158981,
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0.03637281432747841,
0.019664548337459564,
0.0740293487906456,
0.018... |
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