question stringlengths 37 38.8k | group_id stringlengths 2 6 | sentence_embeddings listlengths 768 768 |
|---|---|---|
<p>This relatively simple question collapses neatly into the title. I have large swaths of numerical and categorical data that contain unknown amounts of signal relative to weak data modeling principles. From these data sets, I'm attempting to extract usable signal -- that is, data that is well-ordered, correctly trans... | g68525 | [
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<p>I am trying to understand what looks to be some simple terminology issue, involving $Q_n$ from my book here:</p>
<p><img src="http://i.stack.imgur.com/MiVuH.jpg" alt="enter image description here"></p>
<p>Specifically, I do not understand what they mean when they say $m = {n \choose 2}$, and what they mean when th... | g122 | [
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<p>How can I calculate proportion of variance of an aggregate time-series accounted for by the variance of a sub-series? As I'm not sure what the correct terminology is for explaining my question, I'll illustrate it with an example:</p>
<p>I have a time-series (say, for example, annual alcohol consumption in the USA) ... | g68526 | [
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<p>I am at a loss about what the BUGS/JAGS specification of the following should look like. The background is that one person has four measurements taken by four different instruments. Each instrument is expected to have a different associated error. The R code for generating simulated data (not very elegant) is:</p... | g28583 | [
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<p>Can someone please offer a nice succinct explanation why it is not a good idea to teach students that a p-value is the prob(their findings are due to [random] chance). My understanding is that a p-value is the prob(getting more extreme data | null hypothesis is true). My real interest is <strong>what is the harm... | g28584 | [
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<p>My shortened data is:</p>
<pre><code>y <- c (2,2,1,5,6,7,1,2,1,6,6,7,3,2,4,4,4,4,3,3,9,1,1,9)
</code></pre>
<p>I firstly normalize my data:</p>
<pre><code>y_scale <- scale(y)
</code></pre>
<p>Then, I generate a model dataset with normal distribution based on y_scale's mean and stdev:</p>
<pre><code>y_norm... | g68527 | [
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<p>I've been looking at attendance data for a college library taken during finals week when the library was open for 24 hours. However the staff only took head counts during the hours of 12am to 6am (7 data points per night, for about 11-12 nights, 3 semesters worth of similar counts). I was wondering if, because the d... | g68528 | [
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<p>I am trying to figure out how to control the smoothing parameters in an mgcv:gam model.</p>
<p>I have a binomial variable I am trying to model as primarily a function of x and y coordinates on a fixed grid, plus some other variables with more minor influences. In the past I have constructed a reasonably good local... | g68529 | [
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<p>I have been using z-scores by subtracting the mean (and then dividing by the SD) of the <em>sample</em>, whereas I recently read they actually need to be the <em>population</em> mean and SD. Assuming you are transforming raw scores to z-scores in order to compare within-sample variables (various test scores of the s... | g68530 | [
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<p>Given a linear regression model with all the assumptions checked and validated, I would like to obtain the probability that $Y>y|X=x$. For example for the iris dataset, I would do the following to obtain the probability of $Y>5|X=1,2,3...7$:</p>
<pre><code>plot(Sepal.Length~Petal.Length, data=iris)
lm1<-lm... | g68531 | [
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<p>I'm trying to write an algo for playing some board games using Q/SARSA combined with neural net as valuation approximation. </p>
<p>It works to some extent, but I can't make it to expert level. So for example, my AI can play tic-tac-toe perfectly, or the game <a href="http://en.wikipedia.org/wiki/2048_%28video_game... | g68532 | [
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<p>Is there any way to normalize this variable (attached)? In fact, this is a proportional data (a percentage). But I need transform it in order to do some contrasts.
I try with arcsine transformation: 2 * ARSIN(SQRT(x)). But I can't get an interesting result.
Moreover, If there are any way to get a normal distribution... | g28589 | [
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<p>Whats the probability of 3 brothers being born on the same day of the month in 3 different months? I ask because I'm one of them. Its April, May, and October 12th. What's the difference including whether or not we'd be male/female?</p> | g68533 | [
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<p>In my case, I would like to compare different handwriting to a template handwritten word, and return a single metric to show how closely the input matches the template's shape.</p>
<p>The lines are the same thickness; their main difference should be the curve and angle.</p>
<p>I have already collected and paired u... | g68534 | [
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<p><strong>Input:</strong> $k$ vectors $x^1,\ldots,x^k \in \mathbb{R}^n$, where $x^i \sim \mathcal{N}(x,\mathbb{1} \cdot \sigma_i^2)$.</p>
<p><strong>Goal:</strong> approximate the vector $x$ as well as possible.</p>
<p>The quality of approximation is measured in any reasonable metric such as $\mathbb{L}_1$ norm or P... | g28590 | [
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<p>It is easy to estimate a Poisson regression model using the Newton–Raphson Iterative Technique as it only involves one parameter (mu). However, I am unable to understand how a negative binomial regression model can be estimated using the Newton–Raphson Iterative Technique, as it involve two parameters (mu and disper... | g68535 | [
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<p>I am using regression model to predict values I have. How can evaluate the accuracy of prediction model (I'd like to see how the accuracy of predicted values).</p>
<p>I found different metrics, but it's only used with discrete data. </p>
<ul>
<li>Classification report</li>
<li>Accuracy score</li>
<li>Confusion ma... | g68536 | [
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<p>My graph consists of a computer network topology where each vertex is a physical node/device (depicted using its IP address). Two vertices will have an edge if the nodes have had communication with each other. We call each communication a <em>conversation</em>, which will have multiple packets transferred in both di... | g20814 | [
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<p>I regularly encounter the following scenario: I am presented with a set, $\mathcal{S}$, of $i$ items. </p>
<p>I am assured that $d$ of the $i$ items possess a particular property, $d'$ - and that the rest, $(i-d)$, do not. So the items are in 2 piles: $d'$ and non-$d'$. </p>
<p>(For context, let's say that $i$ is... | g68537 | [
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<p>I am not comfortable with Fisher information, what it measures and how and how is it helpful. Also it's relationship with the Cramer-Rao bound is not apparent to me.</p>
<p>Can someone please give an intuitive explanation of these concepts?</p> | g28592 | [
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<p>I have 4 groups each consisting of 1000 recent college graduates, and I am studying employment immediately after graduation. 2 groups took a business class in college, and 2 groups took a math course in college. Group 1 is a control that has taken neither a business class nor a math course in college. I want to cond... | g68538 | [
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<p>In the general case, if I have a symmetric, invertible (real-valued) matrix where each entry in the matrix has a separate error associated with it (or, in the more general case, where each value has a separate positive and negative error associated with it), how can I <em>rigorously</em> propagate these error values... | g28594 | [
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<p>I have two independent poisson random variables, $X_1$ and $X_2$, with $X_1 \sim \text{Pois}(\lambda_1)$ and $X_2 \sim \text{Pois}(\lambda_2)$. I want to test $H_0:\, \lambda_1 = \lambda_2$ versus the alternative $H_1:\, \lambda_1 \neq \lambda_2$.</p>
<p>I already derived maximum likelihood estimates under null and... | g28595 | [
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<p>Open any statistics textbook and it will urge the need to check the 'precision of our estimates'.</p>
<p>Take the following random variable:</p>
<pre><code>set.seed(55)
x <- rnorm(n=10, mean=0.3453, sd=1)
x
[1] 0.4654391 -1.4670769 0.4968830 -0.7739210 0.3472082 1.5338185 -0.1600439 0.2460656 0.6506532
... | g68539 | [
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<p>This is a beginner’s question on an exercise in Jim Albert’s “Bayesian Computation with R”. Note that while this might be homework, in my case it is not, as I am learning Bayesian methods in R because I think I might use it in my future analyses.</p>
<p>Anyways, while this is a specific question, it probably involv... | g38550 | [
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<p>I have a dataset for around 40k firms over fiscal years 1950-2011 with about 430k firm-years. If I'm not mistaken I have panel-data. In addition, the firms are nested within 9 industries.</p>
<p>I created a unique identifier <code>ticn</code> for each firm. Years are indicated by <code>fyear</code>. For now my vari... | g68540 | [
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<p>I have a sample of the number of bank loans issued each year from the period 2004-2012. I have split the sample in two (2004-2008 and 2009-2012) and want to test if the number of bank loans issued in the second period (2009-2012) is significantly lower than the first period. </p>
<p>Question:<br>
When using the T-t... | g9473 | [
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<p>We know that as the number of independent variables increases, the coefficient of determination $R^2$ will increase but the adjusted $R^2$ may or may not increase. In the following question for the sake of simplicity I shall write only $R^2$ but it must be understood that the question applies to both $R^2$ and adjus... | g42683 | [
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<p>My data is a series of repeated measures in time (14 measures). I am trying to model the variable <code>HbA1c</code> which is a blood test performed at each visit to measure the global blood glucose level. Other predictors are recorded at each visit are BMI, age, insulin dose, and insulin type, etc....</p>
<p>By lo... | g68541 | [
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<p>I have panel data of sales for many stores in two comparable cities. One of the cities holds a special event once a month (<em>the treatment</em>) which is expected to boost sales across the board on that day. I would like to estimate the average treatment effect on the treated, i.e. identify whether or not the spec... | g38552 | [
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<p>I have a number of continuous but really skewed variables in the statistical analyses I am currently performing. Even though I am strongly in favour of keeping them just as they are and relaxing linearity assumptions by using splines, several faculty suggestions favour categorization for various reasons, including e... | g28604 | [
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-0.00867389515042305,
0.014477001503109932,
0.011226437985897064,
0.024813883006572723,
-0.006243405397981405,
0.10621189326047897,
-0.022940490394830704,
0.049874890595674515,
0.... |
<p>I have a set of about ten questions that I would like to use to create groupings from. The responses are all dichotomous (responses are in the form of 1 or 2 where 1 and 2 represent differences in preference discovered through qualitative research). </p>
<p>The questions, were provided in the form: </p>
<pre><cod... | g37456 | [
-0.017208319157361984,
-0.010962607339024544,
0.0014591022627428174,
-0.06591138988733292,
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0.025964735075831413,
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-0.0243663489818573,
0.038649462163448334,
-0.005050621461123228,
0.09186742454767227,
... |
<p>I'm performing regression analysis of some data. I believe I have to use a non-linear model with the form $y = at^b + c$ where $t$ is time. A log transform won't linearize the data here because of the constant term $c$. </p>
<p>When I perform the regression, I get a model that fits the data very well. My R-squared ... | g68542 | [
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0.01602974161505699,
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0... |
<p>Assume that the true (but unknown) relationship in a population between $Y$ and $X1, X2, X3, X4$ is $$Y=\beta_0 + \beta_1 X_1 + \beta_2 X_2 + \beta_3 X_3 + \beta_4 X_4.$$ Further assume that I have a sample from the population that I wish to model using linear regression and I fit the following two regression models... | g68543 | [
0.030912745743989944,
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0.014868679456412792,
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0.043911162763834,
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-0.023009223863482475,
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0.03358403965830803,
0.0052191331051290035,
-... |
<p>I have binary vectors, each with a binary outcome:
for example:</p>
<pre><code>|A|B|C| outcome
1 0 0 -> 0
0 0 1 -> 0
1 0 1 -> 0
0 1 0 -> 1
0 1 1 -> 1
</code></pre>
<p>How can I test which of my attributes (A,B and C in this example) have a significant impact on my outcome? Test the summed quadr... | g68544 | [
0.016515519469976425,
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0.00012159912148490548,
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0.022586772218346596,
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0.... |
<p>In my Bayesian model, I have a random variable representing the amount of money received due to a user's click on an affiliate link on a website. There are several such links with different payouts; in my model I want to capture the uncertainty due to the unknown behaviour of the user. The amounts are typically in t... | g68545 | [
0.021794334053993225,
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0.004761410877108574,
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-0.... |
<p>It was mentioned very briefly in a lecture related to graphical models that two random variables $X_3$ and $X_4$ are both dependent on $X_2$. But even when conditioned on $X_2$, the two variables $X_3$ and $X_4$ could be dependent through some other means. </p>
<p>I wasn't sure what the person meant by this, below... | g38558 | [
-0.01284065842628479,
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0.0028891481924802065,
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0.017479440197348595,
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-0.01186747383326292,
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0.035712044686079025,
-0.02014835551381111,
-0... |
<p>My prof claims that raising a symmetric r.v., like N(0,1), to an odd power gives a distribution with expectation 0. What's the best way to see this?</p> | g21937 | [
-0.01630871184170246,
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0.02869289740920067,
0.03721883147954941,
0.04475852847099304,
0.0... |
<p>I implemented LSA on MATLAB.
I have a $D\times N$ term-document matrix, where $D$: # of words, $N$: # of docs.
I did low-rank approximation using SVD, and got $$X_k = U_k \cdot S_k \cdot V_k'
(D=1000, N=600, K=4)$$</p>
<p>Now I want to classify the documents into 4 classes,
and I know I have to use the col-vectors... | g1362 | [
0.00637496542185545,
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-0.027553709223866463,
-0.015303974971175194,
0.032598212361335754,
0.08404888957738876,
... |
<p>How to calculate discrete interval coverage?</p>
<p>What I know how to do: </p>
<p>If I had a continuous model, I could define a 95% confidence interval for each of my predicted values, and then see how often the actual values were within the confidence interval. I might find that only 88% of the time did my 95% ... | g68546 | [
0.006857159547507763,
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0.013290773145854473,
-0.006407948676496744,
0.04897681623697281,
... |
<p><a href="http://www.jstor.org/stable/2285344" rel="nofollow">Samiuddin, (1976)</a> states:</p>
<p><img src="http://i.stack.imgur.com/jvBNh.png" alt="enter image description here"></p>
<p>or, typset with $\LaTeX$ as originally posted</p>
<blockquote>
<p>We start with the usual noninformative
prior distribution... | g68547 | [
-0.00609587924554944,
-0.04082309082150459,
-0.017823096364736557,
-0.03487500920891762,
0.030893536284565926,
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0.026949435472488403,
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-0.02615445666015148,
0.011880703270435333,
0.06312722712755203,
0.017799004912376404,
0... |
<p>I'm about to apply Kruskal-Wallis test (non-parametric ANOVA) on three groups of unequal length. I was taught/advised to apply Krukal-Wallis only if:</p>
<ul>
<li>dependent variable is at least at ordinal level of measurement</li>
<li>group's $ n > 5 $ (otherwise H statistic is not $ \chi ^2 $ distributed, so ex... | g28616 | [
-0.05397545173764229,
0.011678868904709816,
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0.02160646580159664,
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-0.022328868508338928,
0.006258801091462374,
-0.0015853873919695616,
0.0070707183331251144,
... |
<p>I am going to validate my feature selection algorithm using k-nn classifer.</p> | g68548 | [
-0.03353000804781914,
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0.01773003302514553,
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0.02377757430076599,
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0.008998727425932884,
-0.015496283769607544,
0.026137441396713257,
0.0000053820444918528665,
... |
<p>Why there is a missingNode as 3 as there are no missing values?</p>
<p>I have the data in the following form:</p>
<pre><code>Y Score ot
1 10 3
0 7 2
0 9 2
0 22 1
0 5 2
</code></pre>
<p>Then</p>
<pre><code>rawData <- read.delim("file.txt", header=TRUE, sep=" ");
data <- rawData[,c("Score",... | g28618 | [
0.04919074475765228,
-0.021880855783820152,
-0.003192303469404578,
-0.052851807326078415,
0.05247773975133896,
0.05057266727089882,
0.03132808953523636,
0.02090843953192234,
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-0.0589289590716362,
-0.0205922182649374,
-0.022106721997261047,
0.02623608708381653,
0.012607... |
<p>My data is simple, my independant variable is continous from 0-1000 and the response is either a 1 or a 0. I'm performing a logistic regression to determine the 50% inflection point.</p>
<p>When I put this data into Statgraphics 5.1 I get a different respose from my collegaue who is using Statgraphics XVI (my organ... | g68549 | [
0.03577795997262001,
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0.014132067561149597,
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0.04122622683644295,
0.02018972672522068,
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-0.04303806647658348,
0.04587669298052788,
0.031947292387485504,
0.037933483719825745,
-0.0... |
<ol>
<li><p>Can the Neyman-Pearson lemma apply to the case when a simple null and
a simple alternative don't belong to the same family of distributions?
From its proof, I don't see why it can't.</p>
<p>For example, when the simple null is a normal distribution and the
simple alternative is a exponential distribution.<... | g68550 | [
0.040478408336639404,
-0.01996021717786789,
0.01120738498866558,
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0.005776904057711363,
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0.04373382776975632,
-0.012824068777263165,
0.012271971441805363,
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0.02250390313565731,
0.0... |
<p><a href="http://www.cs.rutgers.edu/~mlittman/courses/lightai03/jain99data.pdf" rel="nofollow">This famous paper</a> points out that any squared error based clustering method (K means being the most common example) tends to generate hyperspherical clusters. However, it does not point to a theoretical justification. <... | g44755 | [
0.07409198582172394,
0.012533027678728104,
0.029077759012579918,
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0.010797807946801186,
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0.00019488691759761423,
0.014973005279898643,
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0.1091136634349823,
0... |
<p>Does model adequacy checking mean "Checking the normality assumption that $\epsilon_{ij}\sim \mathcal{N}(0,\sigma^2)$"? More specifically, does it mean checking that the residuals, $e_{ij}=y_{ij}−\hat{y}_{ij}$, are distributed in this way?</p>
<p>And is an independence check performed by showing that the mean squar... | g28621 | [
0.026575813069939613,
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0.019310273230075836,
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0.014899673871695995,
0.00565333990380168,
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0.046693041920661926,
0.010235019028186798,
0.06460864841938019,
0.011041221208870411,
0.... |
<p>I fitted an hyperbolic distribution to my data with the <code>hyperbFit(mydata,hessian=TRUE)</code> command (package HyperbolicDist). The hessian looks like:</p>
<pre><code>> hyperbfitmymodel$hessian
hyperbPi lZeta lDelta mu
hyperbPi 536.61654 -23.82800 25.62345 26153.16561... | g28622 | [
0.05292446166276932,
-0.028342578560113907,
-0.0029505242127925158,
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0.07549245655536652,
-0.006428018677979708,
0.03113408572971821,
-0.008661588653922081,
-0.0737275704741478,
-0.02871297113597393,
0.008932901546359062,
0.0654832050204277,
0.04014711081981659,
0.030... |
<p>Does anybody know which software provide forecasting with more than two seasonalities? I know R includes tools for double seasonal holt winter forecasting but I am looking for a software which can forecast triple seasonal data.</p> | g68551 | [
0.052353885024785995,
-0.050177231431007385,
0.014613446779549122,
0.03046233206987381,
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0.022090287879109383,
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-0.024565571919083595,
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0.012701334431767464,
0.07175222784280777,
-... |
<p>I am not exactly sure if CrossValidated is the place to ask this question, but decided to give it a shot. This may be thought as an abstract question. I am trying to compare the feasibility of two different methods, let's call them:</p>
<pre><code>Method A
Method B
</code></pre>
<p>Both methods take the same param... | g68552 | [
0.06211208179593086,
-0.05313462018966675,
0.015169395133852959,
-0.024373890832066536,
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0.007912378758192062,
0.024040235206484795,
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0.04115672782063484,
0.005567428655922413,
0.0403444729745388,
0.0551370345056057,
0.0147... |
<p>I encountered this phrase while reading a paper which goes like this -- "These methods lack finite sample error control due to instability". Although it might not be important, the paper deals with a feature selection strategy for classification. </p> | g68553 | [
0.03780519962310791,
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0.015109154395759106,
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0.04053753241896629,
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0.051095329225063324,
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-0.03713594377040863,
0.016186801716685295,
0.004315478727221489,
0.06493999809026718,
0.07... |
<p>let $X_{t}=\frac{4}{5}X_{t-1}+u_{t}$ with $u_t$ a white noise with $\textbf{E}(u^2_{t})=\frac{9}{50}$. assume that $X_{t}$ is affected by ameasurement error,and let $Y_{t}=X_{t}+v_{t}$ where $v_{t}$ is a whine noise uncorrelated with $u_{t}$ and with $\textbf{E}(v^2_{t})=\frac{1}{2}$.</p>
<p>Show that $Y_{t}$ can b... | g68554 | [
-0.002231335500255227,
-0.03192572295665741,
-0.031206462532281876,
-0.04511807858943939,
0.07018128782510757,
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0.05851440876722336,
0.003653613617643714,
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0.049654729664325714,
-0.0384083166718483,
0.06164707988500595,
0.06063289940357208,
0.04870... |
<p>I have data on the effect of treatment on leg shaking. I reused several individuals so I want to know </p>
<ol>
<li>Is there a significant effect of treatment on shaking</li>
<li>Do the reused individuals present some effect or significant variation</li>
</ol>
<p>Nevertheless when I run</p>
<pre><code>model1<... | g68555 | [
-0.020058125257492065,
-0.020861012861132622,
-0.011551015079021454,
-0.04988393560051918,
0.03629017621278763,
-0.00011522790009621531,
0.040469951927661896,
0.04661014676094055,
-0.004353860858827829,
-0.004777069203555584,
-0.012098288163542747,
0.00615351926535368,
-0.023431550711393356,... |
<p>I want to compare two set of variables: </p>
<ul>
<li><p>X1 = All the pairwise distances between individuals from group A and group ref R</p></li>
<li><p>X2 = ALL the pairwise distances between individuals from group B and group ref R</p></li>
</ul>
<p>is it ok to test if the distribution X1 and X2 are different... | g28627 | [
-0.018361054360866547,
-0.059372805058956146,
-0.017870979383587837,
-0.051963675767183304,
0.020295744761824608,
0.0030416613444685936,
0.002083504805341363,
-0.04062824323773384,
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0.007415296975523233,
0.03167451173067093,
0.024509618058800697,
0.005442972760647535,
... |
<p>I recently saw a paper that presented the results of a multiple regression, and then proceeded to also present the results from univariate regressions for the independent variables in which they were most interested.</p>
<p>The multiple regression already showed 4 significant independent variables (interactions wer... | g38567 | [
0.007180303335189819,
0.0582580640912056,
-0.005391442682594061,
0.018805643543601036,
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0.003594896988943219,
0.01353311724960804,
0.02265198342502117,
-0.0367850624024868,
0.02883552946150303,
-0.011282741092145443,
-0.002906771609559655,
-0.0121... |
<p>I would like to put an output from R to my appendix in my thesis; however when I pasted it to Word, the columns were moved.</p>
<p>Do you have any idea how to adjust it to be exactly the same as in R? so that it is easier to read </p> | g68556 | [
0.023783056065440178,
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0.0210020300000906,
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0.010456210933625698,
0.06272254884243011,
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0.07062368839979172,
-0.010953804478049278,
0.025733821094036102,
0.04264890402555466,
-0.00019... |
<p>I have been at it for days and simply can't solve this. I would like to fit a curve with two peaks (i.e. bimodal) to my data set. I have both x and y values in my data (i.e. not a probability distribution data set). </p>
<p>The curve i fit may or may not be made up of two normal distributions (the distributions mig... | g68557 | [
0.0560748390853405,
0.0009284887928515673,
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0.003476976417005062,
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0.002934037009254098,
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-0.032232481986284256,
0.007491673808544874,
0.024165019392967224,
0.04155978560447693,
... |
<p>In “A Comparative Study of Nursing Home Residents …”, <a href="http://www.ncbi.nlm.nih.gov/pubmed/14706124" rel="nofollow">Aigner et al.</a> write (p. 20)</p>
<blockquote>
<p>Acute visits were significantly higher for the nurse practiticoner/physician team at 3.0 visits per year (± 2.4) versus 1.2 visits per year... | g28630 | [
0.0002929836336988956,
0.008642188273370266,
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0.023596394807100296,
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0.03345765173435211,
0.006412059534341097,
0.08882390707731247,
0.029505332931876183,
0.017399920150637627,
... |
<p>I understand that variance can be zero if all data points are equal. </p>
<p>Can anybody state an example, where sample variance is equal to sample mean and what - if any - is its significance to distributions like the Poisson.</p> | g28632 | [
0.034887947142124176,
0.019207503646612167,
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-0.05109510198235512,
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0.0022060128394514322,
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-0.... |
<p>Suppose $X_1,\ldots,X_n$ are a random sample of a continuous and strictly increasing distribution $F(x)$ with mean $\mu$. If</p>
<p>$$
Y_i = \begin {cases} 2 & \text{if}\ X_i>\mu \\
1 & \text{if} \ X_i\leq\mu \end {cases}
$$</p>
<p>Determine the MLE of parameter $\mu$</p> | g38571 | [
0.03044712170958519,
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0.0014102422865107656,
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0.015990063548088074,
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0.0324043408036232,
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0.02543691359460354,
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<p>I ran a simple psychology experiment that included 4 conditions, each containing 8 blocks of training. There were different participants in each condition. Hence, condition and block and subject and block are crossed, but subject is nested in condition. I'm trying to do a basic repeated measures anova to test for ef... | g38572 | [
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<p>I have a database of second hand cars. It contains (among other things) the asking price, the mileage, the fuel consumption and the year it was built. </p>
<p>I would like to know how much the value depreciates due to time (only), and due to mileage (only). </p>
<p>So for car model X, I'd like to know:
- how much ... | g68558 | [
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<p>L2 regularized logistic regression differs with L2 regularized support vector machine with their loss function. Are there more deep differences for these two models? I tried several data sets, and found L2 regularized logistic regression are always better than L2 regulared support vector machine. Are there any refer... | g68559 | [
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<p>first of all the basic idea of my experiment: changes/differences of reaction time (RT) after 3 different types of sport (a: no jogging=SP1; b: 10min of jogging=SP2 and c: 30min of jogging=SP3);
36 subjects (SUB) are randomly assigned to one of the 6 possible combinations of “sport” (abc, acb, bac, bca, cab and cba,... | g29902 | [
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<p>How to define confusion matrix of the database and the classification rules are found below. And calculation precision and recall.</p>
<p>MinSup = 3% and MinConf = 30%</p>
<pre><code>@attribute temperature real
@attribute humidity real
@attribute windy {TRUE, FALSE}
@attribute play {yes, no}
No. outlook tempe... | g28634 | [
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<p>I am currently looking for datasets that I can use to predict how an individual voter will vote in a US election. </p>
<p>Ideally, the dataset that I am looking for includes socioeconomic features such as age, sex, income, county, and include an outcome variable for the party/candidate that this person cast their v... | g39800 | [
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<p>I'm designing an experiment where subjects are asked to choose their favorite object among 3 different objects. Each subject gets the same 3 objects to choose from. How can I determine if one of the objects is favorited over the other objects in this experiment? The data looks like this:</p>
<pre><code>Subject Obj... | g68560 | [
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<p>Let $X_1,\dots,X_n$ are i.i.d. copies of $X$, however I don't know the value of them. I only know the distance for every pair $(i,j)$.</p>
<p>Now, assume that we are given $Y$ and $Z$ which are also i.i.d. copies of $X$, and we will be interested to estimate the distance between $Y$ and $Z$. Is there a literature r... | g68561 | [
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<p><strong>Update</strong>
So I've done some of my own work on transformational methods, and the best I can get is what I call an s transform as detailed in this workbook; however, various attempts at trying to mean adjust on the Summary page show that sometimes the values get fudged/overlap each other at .5...</p>
<p... | g49807 | [
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<p>I have data coming in the following format: UserId, GroupId, Frequency (how many times the user chose the group), Max timestamp (the last time the user chose the group).</p>
<p>Based on this dataset we need to figure out which groups look alike. I was thinking of using collaborative filtering but I have 3 concerns:... | g844 | [
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<p>The 16-year-old Chinese swimmer Ye Shiwen swam more than 5 seconds faster than her personal best in women's 400m individual medley in London 2012 Olympics, winning her a gold. Her performance received high exposure to media and mixed comments, even some controversy. For example, Nature published a news report titled... | g11628 | [
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<p>Given: </p>
<p>Crude incidence rate per 100,000: 164</p>
<p>population: 211,101</p>
<p>95% CI: 147-182</p>
<p>What is the standard deviation of the incidence rate :</p>
<p>My calc:
Standard error:(182-147) / (2 x 1.96) = 8.93</p>
<p>Standard deviation = 8.93 x sqrt(211,101) = 4103</p>
<p>This can't be right, ... | g68562 | [
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<p>Sorry, this is a homework help question:</p>
<blockquote>
<p>In a bacterial growth experiment, ten μ (exponential growth rate constant) data points have been collected: one each of nine different concentrations of an antibiotic, plus one control (no antibiotic). What is the most appropriate statistical treatment ... | g68563 | [
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<p>I am using R to examine the relationship between two variables in a small data set ($n=16$). </p>
<p>My problem is that I'm not really sure how to handle the analysis (read: I'm in deeper waters than I've traveled before).</p>
<p>Do I use Spearman's Rho to calculate the rank coefficient? Or do I assume normality a... | g37460 | [
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<p>Stacked area charts work great when charting raw values, averages, counts, and percentage of total. The sum of the values across the different groups will add up to that of the entire set.</p>
<p>But what about in the case when the value being charted is a Median, Geo Mean, or any Percentile? In these cases the sum... | g68564 | [
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<p>I wonder what is wrong with my own answer for the problem which I have shared below, could you please help me some about that:</p>
<p>" Suppose that we have 12 observation units $ ( n=12 ) $ in a statistical investigation. What is the "t-table" value $ ( {\downarrow}v^{ \backslash ^{\large{p} \, \rightarrow} } \; ... | g38590 | [
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<p>Suppose we have a Cox-PH model and death is the outcome of interest. Suppose we have the predictors $X_1, X_2$ and $X_3$. Then does the PH assumption mean that for any person (i.e. arbitrary values of $X_1,X_2$ and $X_3$) the hazard of death is $c \cdot h_{0}(t)$ where $c$ is a constant? So the hazard function is th... | g28639 | [
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<p>Testing for cointegration tests to see if the residuals from a regression between the two variables is a stationary process. So wouldn't a test on those residuals for heteroskedasticity be the same thing? To detect if the variance of the errors is stable and the error terms are not a random walk? Wouldn't a White te... | g38593 | [
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<p>what I mean by war stories is "tales from experience with real problems" where researchers "describe real problems and the process that led to the algorithm that solved the problems". Here are some examples (<a href="http://books.google.co.jp/books?id=7XUSn0IKQEgC&lpg=PR6&ots=z78DQOGV-h&dq=algorithm%20de... | g38058 | [
0.05659191310405731,
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0.01648261956870556,
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0.0944463238120079,
0.048785... |
<p>I'm using a negative binomial GLM to predict individual level scores on a psychometric test that ranges from 0-27 and presenting the coefficient "incidence rate ratios".</p>
<p>It seems a little strange to use the term "incidence rate ratio" when actually it is a psychometric score ratio. Should I still use the ter... | g68565 | [
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<p>Im looking for some pointers on how to perform a Monte Carlo simulation. Say im conducting a survey of how late flights are for a certain airline. I amass 1000 records, and plot a cumulative sum of these values. I want to determine how likely it is to have several flights grouped together that a decrease in the cumu... | g68566 | [
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<p>I am now trying to use PRODCLIN to do the mediation analysis to obtain a confidence interval for binary single mediation analysis. <a href="http://ripl.faculty.asu.edu/downloadable-programs/prodclin/" rel="nofollow">http://ripl.faculty.asu.edu/downloadable-programs/prodclin/</a> All of the variables I used are binar... | g68567 | [
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<p>Assume for example a trivariate Gaussian model:
$$
{\boldsymbol Y}_1, \ldots, {\boldsymbol Y}_n \sim_{\text{iid}} {\cal N}_3\left({\boldsymbol \mu}, \Sigma\right) \quad (*)
$$
with ${\boldsymbol \mu} = (\mu_1,\mu_2,\mu_3)'$. </p>
<p>The Bayesian conjugate theory of this model is well known.
This model is the most ... | g68568 | [
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<p>I calculate <code>percentile ranks</code> based on the method at <a href="http://www.psychstat.missouristate.edu/introbook/sbk14m.htm" rel="nofollow">http://www.psychstat.missouristate.edu/introbook/sbk14m.htm</a></p>
<p>I need to assign ranks to a dataset where ranks are from <code>1-to-N</code>. Since N may or m... | g68569 | [
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<p>Oversimplifying a bit, I have about a million records that record the entry time and exit time of people in a system spanning about ten years. Every record has an entry time, but not every record has an exit time. The mean time in the system is ~1 year. </p>
<p>The missing exit times happen for two reasons:</p>
... | g68570 | [
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<p>What are the usual assumptions for linear regression? </p>
<p>Do they include:</p>
<ol>
<li>a linear relationship between the independent and dependent variable</li>
<li>independent errors</li>
<li>normal distribution of errors</li>
<li>homoscedasticity</li>
</ol>
<p>Are there any others?</p> | g49560 | [
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<p>I'm currently working on a panel of 4 countries and 29 years data. I want to arrange my variables <em>GDP</em>, <em>government consumption</em>, <em>government investment</em>, and <em>revenues</em> according to Cholesky ordering. Can anyone tell me that how I do this in Stata? </p>
<p>I start my panel estimation i... | g68571 | [
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<p>i'm not sure how to google for this as i am not very familiar with time series analysis.</p>
<p>i have 500 websites, and i am measuring the number of visitors to each website each day. at some point, i turn on SEO (search engine optimization) for each of the websites. this happens on different days for different ... | g37657 | [
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<p>Actually the solve the SVM is to solve the following Lagrangian Equation:<img src="http://i.stack.imgur.com/mF7lk.jpg" alt="enter image description here"> </p>
<p>If we don't use kernel function, $\langle x^{(i)},x^{(j)}\rangle$ is just the vector vector inner product. The $a_ia_j\langle x^{(j)},x^{(j)}\rangle $... | g44505 | [
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<p>Assume you draw a uniformly distributed random number between 0 and 1 <em>n</em> times. How would one go about calculating the expected <em>minimum</em> number drawn after n trials? </p>
<p>In addition, how would one go about calculating a confidence interval to state that the minimum number drawn is in the inter... | g28648 | [
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<p>The R command <code>hist(pmax(rnorm(10),rnorm(10)))</code> gives a histogram of random variable Y, where Y is the maximum observation of two independent Gaussians. </p>
<ul>
<li>How can I mathematically determine the probability that Y is greater than zero?</li>
<li>How can I use a simulation to determine the proba... | g37441 | [
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0.... |
<p>I am interested in doing a nonparametric hypothesis test in Stata. I have 2 series of data, each time series and that overlap in time period. 10 time periods each.</p>
<p>I am interested in a test that checks whether the series are trending similarly. I am not interested in the levels.</p>
<p>For example, suppo... | g28650 | [
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0.... |
<p>I have to test one predictor associate with 10 responses, the predictor is nominal, and response are continuous, so what kind of test can be used to test the association between them?</p> | g68572 | [
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-0.03359099105000496,
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<p>If I have a variable $X$ whose Gaussian distribution is known and let $f$ be a known function, is there a way to compute $f(X)$ <em>i.e.</em> the resulting Gaussian distribution from this? Is the result actually a Gaussian distribution? </p> | g68573 | [
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-0... |
<p>I am currently working on analyzing a case and I need some help with the statistics. </p>
<p>When a certain woman tried to find an insurance for her car, she was told that the premium she had to pay would be more than average, based on the fact that she was a woman. According to the insurance company, on average, w... | g40385 | [
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0.028917398303747177,
0.026981603354215622,
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0.07654915750026703,
-0.0... |
<p>So, when doing polling, we use binomial distribution to capture the data (in case there are only two choices.). My question is, let us say that estimated percentage according to the poll that supported Obama was 47%. Then we would be able to set $p = 0.47$ and calculate standard error when given the number of sample... | g49399 | [
0.015084282495081425,
-0.031115565448999405,
0.014150558039546013,
0.0020766446832567453,
-0.024561546742916107,
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0.045449670404195786,
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-0.023255953565239906,
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<p>In class, we've been learning a myriad of really interesting techniques to sample from a given distribution, filter online data, particle filters, etc. </p>
<p>My issue is that when I take some real-world data and plot it, the distribution is clearly not Gaussian. So, I need to estimate some distribution. Or, in... | g5543 | [
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0.0387641079723835,
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0.06863553822040558,
0.0120... |
<p>Say I have a random variable (such as concentration) that is defined spatially by some function $C(x)$. </p>
<p>I would like to derive a PDF $(f(C))$ from the concentration function $C(x)$ over some domain of x, so that if I pick a random value of $x$, $f(C)$ describes the probability of $C$.</p>
<p>Here's an exam... | g68574 | [
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0.07486938685178757,
-0... |
<p>I have a conceptual understanding of locality-sensitive hashing (LSH) in relation to near-neighbour search. However, the articles that I have read so far seem to gloss over the details of how LSH can be used for probabilistic dimensionality reduction (e.g. <a href="http://en.wikipedia.org/wiki/Locality-sensitive_has... | g68575 | [
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0.04085497185587883,
0.01... |
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