question stringlengths 37 38.8k | group_id stringlengths 2 6 | sentence_embeddings listlengths 768 768 |
|---|---|---|
<p>I am having a few problems with my analysis and hope that somebody can help me out. About my design: I have 120 respondents, who I showed each 7 facebook posts out of a pool of 16 (randomly assigned). Each facebook posts was "ranked" by them on 1 DV (shares) and 3 IV (entertainment, information and emotion).</p>
<p... | g66776 | [
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<p>I realized that, never been observed words in training sets, decrease test probaility of documents being spam and not spam after i mentioned <a href="http://stats.stackexchange.com/questions/98986/naive-bayes-non-dictionary-term-in-test-document">here</a> and this <a href="http://stackoverflow.com/questions/8680243/... | g34481 | [
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<p>Zuur 2013 Beginners Guide to GLM & GLMM suggests validating a Poisson regression by plotting Pearsons residuals against fitted values. Zuur states we shouldn't see the residuals fanning out as fitted values increase, like attached (hand drawn) plot. </p>
<p>But I thought a key characteristic of the Poisson dist... | g66777 | [
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<p>I have data on two groups...I have one independent variable (times 1, 2, and 3) and a dependent variable fitness score (which includes score of a person's heart rate in five stages of the test, minutes they achieved, distance they achieved and rated perceived exertion). </p>
<p>I'm leaning toward one-way repeated m... | g66778 | [
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<p>The Maximum Entropy Bootstrap (meboot) let's you create random realizations of time series.
I have tried to make sense of the description of the algorithm in H. D. Vinod's paper <strong>'Maximum entropy ensembles for time series inference in economics'</strong> where it is divided into 7 steps.</p>
<ol>
<li>First t... | g66779 | [
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<p>I have this model, nonlinear in the parameters</p>
<p>$
y = \beta_0^2 + \beta_0 \beta_1 x_i
$</p>
<p>exist a known estimation of parameters ? </p> | g66780 | [
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<p>I'm trying to fit a generalised pareto distribution to a simulated dataset using JAGS and runjags. When doing so, I get very strange density and mixing plots for the mu parameter. The sigma and xi parameters are estimated as expected. </p>
<p><strong>How should I interpret these plots, and proceed to fix my model?<... | g66781 | [
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<p>From <a href="http://en.wikipedia.org/wiki/Mixed-design_analysis_of_variance" rel="nofollow">Wikipedia</a></p>
<blockquote>
<p>a <strong>mixed-design</strong> analysis of variance model (also known as a <strong>split-plot</strong> ANOVA) is used to test for differences between two or more independent groups whils... | g66782 | [
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0.01... |
<p>I don't have SPSS. But judging from the documentation you can find on the internet, SPSS "<a href="http://pic.dhe.ibm.com/infocenter/spssstat/v20r0m0/index.jsp?topic=/com.ibm.spss.statistics.help/alg_twostep.htm" rel="nofollow">Two-Step Clustering</a>" seems to be closely related to BIRCH clustering:</p>
<blockquot... | g17214 | [
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<p>This is a general question on logistic regression result reporting for a publication.</p>
<p>We have an example where two well correlated ($r=0.4, p=0.001$) blood parameters (<code>blood parameter1</code> and <code>blood parameter2</code>) are associated with blood pressure in mixed sample of men and women, however... | g66783 | [
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<p>I'm kind of new doing data mining, so sorry if my question is not very clear. </p>
<p>I'm working in a project that is aiming to do data mining over the interactions of the students with a e-learning platform. So, I'm trying to generate decision trees with some data that I collected (number of times that student us... | g37478 | [
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<p>I am trying to simulate a signal produced from a GMM of 3 mixtures. Here's MATLAB code</p>
<pre><code>mix1 = -0.4 + 0.01*randn(10000,1);
mix2 = -5 + 0.02*randn(10000,1);
mix3 = 10 + 0.1*randn(10000,1);
gmm = mix1 + mix2 + mix3;
[f,x] = ksdensity(gmm);
plot(x,f)
</code></pre>
<p>I expected to see 3 mixtures (i.e... | g4998 | [
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0.0... |
<p>Sometimes they ask questions in different orders, or use different prompts.</p>
<p>Or datasets with instruments (with at least one variable randomized)?</p>
<p>I would like to use at least one of them for my causal modelling course (Stat 566), whose syllabus is at <a href="https://www.stat.washington.edu/tsr/s566/... | g25971 | [
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<p>I saw a journal article [1] saying that he constructed the following S-curve model :</p>
<p>$$y=\exp\left({\beta_1 + \frac{\beta_2}{x}}\right) + \mathrm{residual}$$</p>
<p>The topic was about a global regression model.</p>
<p><strong>I just cant understand how did he make it. Do you guys know how?</strong></p>
<... | g66784 | [
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<p>I am using R software (R commander) to cluster my data. I have a smaller subset of my data containing 200 rows and about 800 columns. I am getting the following error when trying kmeans cluster and plot on a graph:</p>
<blockquote>
<p>'princomp' can only be used with more units than variables</p>
</blockquote>
<... | g25973 | [
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<p>I have 100,000 students who have each answered some multiple choice questions. Given their performance I want to work out what the chances are of a particular student answering the next question correctly. </p>
<ul>
<li>not each student has answered every question</li>
<li>the probability of getting a question corr... | g66785 | [
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0.04127780... |
<p>I am working with a time series data and found that $a_t$ Granger causes $b_{t+1}$ and $b_t$ granger causes $a_{t+1}$. The results were obtained through Stata. </p>
<ol>
<li><p>With the coefficients obtained, is it possible to determine which Granger causal direction is stronger? If it can't be determined by just l... | g25975 | [
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<p>PnL can take large negative values, and its variance increases over time as the firm grows. If we do differencing, an increasing variance remains. If we take log, negative values cannot be defined. How do you stationarize this type of data for time series analysis? Please assume that we cannot decompose PnL into und... | g66786 | [
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<p>The histogram of my dependent variable is as following:</p>
<p><img src="http://i.stack.imgur.com/H6XlW.jpg" alt="enter image description here"></p>
<p>I draw the scatter plot of my dependent variable and independent variable, and the result is as following picture? I am wondering if the skewness of the dependent ... | g29456 | [
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<p>I'm wondering how to calculate the C-Index for determining a 'good' number of groups in a cluster analysis in Stata? It's mentioned in this post (<a href="http://stats.stackexchange.com/questions/52838/what-is-an-acceptable-value-of-the-calinski-harabasz-ch-criterion/52863#52863">What is an acceptable value of the C... | g35545 | [
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<p>English is not my first language. Here are my questions.</p>
<p>I am using proportions ((0.1, 0.25, 0.25, 0.4) to generate 4 classes of data (1 variable 4 levels) in SAS based on the code below,</p>
<hr>
<pre><code>data NativeBMI (drop = i) ;
array prob [4] (0.1,0.25,0.25,0.4);
call streami... | g66787 | [
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<p>I am applying a Bayesian classifier and would like to find out the f1 score. I determined the TP, TN, FP, TP. Unfortunately I had to find out that in my cross-validation almost in all test scenarios only TP and FP are non-zero (so TN=0, FN=0). Probably this is due to the fact that the ratio of the amount of data of ... | g66788 | [
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<p>I'm working with model 2 of INLA's <a href="http://www.r-inla.org/examples/case-studies/martino-and-rue-2010/code-for-the-zambia-example" rel="nofollow">Zambia example</a> in R:</p>
<pre><code>formula.mod2 = hazstd ~ f(agc, model = "rw2") +
f(district, model="besag", graph = g, param = c(1,0.01)) +
f(distr.unst... | g25987 | [
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... |
<p>I am working with a large scale deterministic model, which attempts to simulate CO2 emissions in different regions. When compared to historic data, the model output suffers from systematic biases.
Here are plots for two regions (model output in blue, historic data in red) :</p>
<p><img src="http://imgur.com/McCB6i... | g66789 | [
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<p>My plain regression looks as follows:</p>
<p>tendaystockreturn = alpha + beta * dummy variable that takes a value of 1 in case a director purchases shares</p>
<p>Now I want to test whether a subgroup of directors will have a higher beta. In other words,
I want to know whether the beta of a subgroup differs from th... | g25988 | [
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<p>In chapter 2 ESL book authors write: Let's look at example of linear model in a classification context<img src="http://i.stack.imgur.com/ANaTc.png" alt="enter image description here"> </p>
<p>They fit a simple linear model $g = 0.3290614 -0.0226360\cdot x_1 + 0.2495983 \cdot x_2 + e$, </p>
<p>where $g$ is given ... | g66790 | [
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<p>Im analyzing time-series to detect when the y-value is so flat that one can assume there is an underlying factor limiting y from being higher. Is there a methodology or statistical discipline that do this kind of analyis automatically? Im after a name I can put in Google that points me to books, articles etc.</p>
<... | g66791 | [
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<p>So if you have $N \sim \mathrm{Poisson}(\lambda)$ or $N \sim \mathrm{Binomial}(n,p)$ I'm curious about the convolution $$X = \sum_{i=1}^N X_i$$
(where $X_i \sim \mathrm{Normal}(\mu, \sigma)$ and $X=0$ if $N=0$)
I guess alternatively this is the compound distribution $$\mathrm{Normal}(N\cdot\mu, \sqrt{N}\cdot\sigma)$... | g66792 | [
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<p>I am trying to create a decision-tree out of a number of attributes, where there are only two final classes and the classes are highly unbalanced (Class 1: 95.5%; Class 2: 4.5%).</p>
<p>The idea is to profile the members of Class 2. For example, Class 2 members have attribute 1 >= 8, attribute 2 < 6, attribute 3... | g66793 | [
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<p>Could someone point me to a good resource for estimating power for detecting treatment heterogeneity via interactions in MR? </p>
<p>Let's assume that individuals will be randomized to two study arms. To estimate heterogeneity (moderation), we would regress the continuous outcome on an indicator of assignment to tr... | g66794 | [
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0.0074392021633684635,
0.015076891519129276,
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0.0333666056394577,
0.060214102268218994,
0.02298647165298462,
-0.03366229683160782,
0.0252... |
<p>I would be grateful for general guidance/advice about data analysis with some data that is problematic for me because of the small sample size, and the large number of categorical data. I realize this question is a bit vague, but that's because I'm not sure what to do. I'd like to come up with some good descripive c... | g25999 | [
-0.02519443817436695,
0.01597319357097149,
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0.00280163181014359,
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0.04740910232067108,
0.02... |
<p>Think you can help with this.
I´ve run a set of candidate hurdle models on insect abundance data with pscl package for R.
These models had an abundance part with a truncated negative binomial distribution; and an ocurrence part with binomial distribution.
I wish to calculate the model parameter estimates and its CI... | g66795 | [
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0.02130541019141674,
0.01732501946389675,
0.0371... |
<p>I have a theoretical growth function that can be perturbed by events, and I'd like to estimate the growth parameters as well as the perturbation, and the rate of falloff after that perturbation.</p>
<p>I'm thinking of using a logistic function to model the effect of the event and the falloff of that effect (if any)... | g29458 | [
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0.01911722868680954,
0.076... |
<p>If I want to conduct a randomised study in 2 sites comparing two clinical treatment arms, and every site is expected to include 60-80 patients, is it acceptable to randomise every new patient with simple coin toss (one centralised scheme for all patients, regardless of site) or is some stratified randomisation more ... | g23428 | [
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<p>I have the following problem and I know I can solve it using PCA / SVD, I just can get to write it properly. </p>
<p>I have many sensors, each produces M = 3500 samples of a signal.<br>
The signal of each sensor is a little different from the other.
I have N = 256 Sensors.</p>
<p>Now, I want to build a dictionary... | g66796 | [
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0.02021545171737671,
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0.... |
<p>How do I calculate the uncertainties in linearly interpolated values from a given tabulated function? </p>
<hr>
<p>I am just coming back into the fold after a bit of a hiatus, and am having trouble jumpstarting my brain.</p>
<p>I have a tabulated function $(x_i, y_i, e_i)$, where $x_i$ is on an irregular grid a... | g66797 | [
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<p>and apologies if this is an overly simple question.
I am doing an A/B mailing (where we send out two different solicitation letters). It's going out to past donors so we have some information on them and I have a master list of about 18,000 eligible donors. The point is to see which letter produces more and/or grea... | g66798 | [
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0.014050031080842018,
0.042678434401750565,
0.0000280852345895255,
0.053814537823200226,
... |
<p>I am running a multiple linear regression using SPSS to test the effect of ethnicity and ethnic/racial attitudes or perceptions on political predispositions. </p>
<p>One model, as an example, looks like this:</p>
<p>DV: 'support for democracy' (1-7 scale)
Controls: age, gender, education etc.
Predictors: Ethnicity... | g26005 | [
0.03529709205031395,
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0.005243147723376751,
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0.082426... |
<p>I want to calculate the area under the first derivate. Can I do that with splinefun()?</p>
<pre><code>Year <- c(1959, 1960, 1961, 1962, 1963, 1964, 1965, 1966, 1967, 1968, 1969)
Population <- c(4835, 4970, 5085, 5160, 5310, 5260, 5235, 5255, 5235, 5210, 5175)
sample <- data.frame(Year, Population)
sample
p... | g26006 | [
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0.035889241844415665,
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<p>What would you use to categorise or rank a Resume/CV with machine learning?</p>
<p>I would like to make particular CVs stand out to recruiters.</p> | g66799 | [
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0.045561667531728745,
0.0503494068980217,
0.055544983595609665,
0.08121570944786072,
-... |
<p>let $X,Y$ are two independent random variables Bernoulli with probability $P$. how can calculate $E(X^Y|X+Y=1)$</p> | g26008 | [
-0.0029884607065469027,
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0.026240823790431023,
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0.018533173948526382,
... |
<p>I have been reading about the <strong>Supervised</strong> and <strong>Unsupervised learning</strong>. What I came to know through <a href="http://stats.stackexchange.com/questions/517/unsupervised-supervised-and-semi-supervised-learning">this link</a> is that in case of Supervised learning you have a set of input an... | g66800 | [
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0.00416094996035099,
0.0550897978246212,
0.017... |
<p>I am using a data set with <strong>18 features</strong> with True/False output (Related to mobile ad targeting). True values occurs only <strong>0.4 %</strong> of the time. So, I have used sampling to keep the ratio of True and False classes nearly 1:1. I have used logistic regression using python's scikit learn. Ho... | g26009 | [
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0.009228821843862534,
0.0170174241065979,
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0.047... |
<p>I have a series of physicians' claims submissions. I would like to perform cluster analysis as an exploratory tool to find patterns in how physicians bill based on things like Revenue Codes, Procedure Codes, etc. The data are all polytomous, and from my basic understanding, a latent class algorithm is appropriate fo... | g66801 | [
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0.028162656351923943,
0.08760461956262589,
0.02... |
<p>I am analyzing data from two surveys that I merged together:</p>
<ul>
<li><p>School staff survey, for years 2005-06 and 2007-08</p></li>
<li><p>School students survey, for years 2005-06 through 2008-09</p></li>
</ul>
<p>For both of these data sets, I have observations (at the student or staff level) from 3 differe... | g5115 | [
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0.0784512311220169,
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0.043685171753168106,
0... |
<p>I attempted to run lasso on a 12 X 52 matrix (11 predictors) using this MATLAB function <a href="http://www.mathworks.com.au/help/stats/lasso.html" rel="nofollow">http://www.mathworks.com.au/help/stats/lasso.html</a>. I found that the results converged to zero.</p>
<p>How should I interpret this?</p>
<p>In the int... | g66802 | [
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0.0021582189947366714,
0.06498228013515472,
0... |
<p>I have a little problem that is making me freaking out.
I have to write procedure for an online acquisition process of a multivariate time series.
At every time interval (for example 1 second), I get a new sample, which is basically a floating point vector of size N.
The operation I need to do is a little bit tricky... | g66803 | [
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0.010180171579122543,
0.008092527277767658,
0.05095576122403145,
0.026837700977921486,
-0.... |
<p>I must clarify immediately that I am a practicing software developer, not a statistician, and that my college stats class was a <em>very</em> long time ago…</p>
<p>That said, I would like to know if there is a method for accumulating a set of descriptive statistics that could then be used to produce a boxplot, that... | g26013 | [
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0.02158103697001934,
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0.06780008226633072,
0.03... |
<blockquote>
<p>The one used by option "ward.D" (equivalent to the only Ward option
"ward" in R versions <= 3.0.3) does not implement Ward's (1963)
clustering criterion, whereas option "ward.D2" implements that
criterion (Murtagh and Legendre 2013).</p>
</blockquote>
<p>(<a href="http://stat.ethz.ch/R-manua... | g66804 | [
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-0.05266571789979935,
0.03798376023769379,
0.010685832239687443,
0.09078744053840637,
0... |
<p>It seems that for calculation of Cohen's $d$ (an estimate of effect size), you should use the difference in means (or in one-sample case, from baseline), divided by $SD$, if that information is available:
$$
\frac{\bar X_1 - \bar X_2}{SD}
$$
However, when you only have the $t$-statistic and the degrees of freedom ($... | g26017 | [
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0.036584340035915375,
0.04632723331451416,
0.00... |
<p>An interesting property of Gaussian Processes is estimating the uncertainty range. This uncertainty range of prediction can potentially capture the actual measurements.</p>
<p>I am wondering, how many times or with what probability this uncertainty range is able to capture the measurement and why ?</p> | g46432 | [
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<p>This may seem a trivial question but I have a fundamental problem in understanding learning. </p>
<ol>
<li><p>In supervised learning, given and input-output pair, what are we learning? Are we learning the inputs (say features) or the output?
For example, In terms of linear system, let a system be y=Ax ; y is the ou... | g66805 | [
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... |
<p>My histogram of expected income is as below.</p>
<p>As you can see, income is highly right skewed. I want to divide individuals with regard to income - for example into Low, Middle, and High, and then I want to compare the other properties of individuals in each of the three groups. </p>
<p>Any idea about dividing... | g66806 | [
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<p>Assume I have this kind of data:</p>
<p>$
A_{11}\quad A_{21} \\
A_{12}\quad A_{22} \\
A_{13}\quad A_{23} \\
B_{11}\quad B_{21} \\
B_{12}\quad B_{22} \\
B_{13}\quad B_{23} \\
C_{11}\quad C_{21} \\
C_{12}\quad C_{22} \\
C_{13}\quad C_{22} \\
...\quad ... \\
$</p>
<p>where $A$, $B$, $C$, ... represent different indiv... | g26019 | [
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0.05218927562236786,
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-... |
<p>(Apologies for the poor title, I didn't know what what to type in)</p>
<p>I am having a problem with the second part of this question (an example question from a past stochastic course I took):</p>
<hr>
<blockquote>
<p>Consider the simple linear birth and death process and the partial
differential equation</p>... | g66807 | [
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<p>My current research deals with landslide size frequency distribution which has been fit to a three-parameter inverse gamma function and a double Pareto function by previous researchers. I am trained as a civil engineer and can't make sense of how to build a program to fit my data in Fortran, MATLAB or R because I'm ... | g66808 | [
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0.010487335734069347,
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<p>I want to do a survey to determine how satisfied the (16) employees are with the company training program. The survey has 30 questions, each using a 5 point Likert scale for responses. The questions are divided into different groups (9 for the utility of the program, 6 regarding the trainer, 7 regarding the balance ... | g66809 | [
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<p>If I know only that the arrival process is Poisson, and I observe it for a pre-chosen (say, unit) period of time, observing $k$ arrivals, is it meaningful to describe an estimate of its time parameter from the observation as (A) maximum-likelihood, (B) minimum-variance, or (C) unbiased if $k$ is very small? If $k$ i... | g66810 | [
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0.02218543365597725,
... |
<p>I would like to create a temporal model showing the likelihood (I am sure this is not used in the correct context) that certain size avocados grow from smallest, small, bigger, biggest. I have considered using a linear regression, but it should be simplified, such that the parameters are entered and an output is cr... | g66811 | [
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0.0033610903192311525,
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0.0060558924451470375,
0.09147021919488907,
... |
<p>I have designed a questionnaire to test which of three motivational constructs can best be used to describe learners motivation. 25 statements were designed to test the three constructs (each question relating to one of the three), they were randomly ordered and participants were asked to respond to each statement ... | g66812 | [
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0.0106333764269948,
0.0012382665881887078,
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0.034482840448617935,
0.047... |
<p>My problem with understanding this expression might come from the fact that English is not my first language, but I don't understand why it's used in this way.</p>
<p>The marginal mean is typically the mean of a group or subgroup's measures of a variable in an experiment, but why not just use the word mean? What's ... | g26025 | [
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0.01875976473093033,
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0.005518695339560509,
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-0.07004410773515701,
0.03959263861179352,
0.03676605969667435,
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0.038... |
<p>I am trying to implement logistic regression using the following algorithm:</p>
<ol>
<li>fit a simple linear model $y \sim Xb_0$</li>
<li>calculate $W = \frac{e^{Xb_0}}{(1+e^{Xb_0})^2}$</li>
<li>calculate $z = Xb_0 + y \cdot \frac{(1+e^{Xb_0})^2}{e^{Xb_0}} - (1+e^{Xb_0})$ (the square and dot product means element-w... | g66813 | [
0.00015629295376129448,
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0.0547933354973793,
0.07399826496839523,
0.0512... |
<p>I know the rank of $\Sigma^{-1}m m'$ is $1$. How can I find the eigenvalue and eigenvector of it? ($\Sigma^{-1}$ is the inverse of a covariance matrix and $m$ is a mean vector.)</p> | g26029 | [
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<p>The question is in the title.</p>
<p>The coefficient of determination or </p>
<p>$
R^2 \equiv 1 - \frac{ss_{res}}{ss_{tot}}
$</p>
<p>is valid in a nonlinear model? Why? </p> | g11202 | [
0.011471091769635677,
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<p>I'm working with the really nice <code>rugarch</code>-package and currently have an issue with respect to the news impact curves (NIC).</p>
<p>In an attempt to plot several NIC into the same plot I realized that while the NIC for the sGARCH, the gjrGARCH and the eGARCH are given with respect to the $\epsilon_{t-1}$... | g66814 | [
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<p>Suppose we have a bivariate normal variable $\mathbf{x}= (x_1, x_2)$ with mean $\mu_1$ and $\mu_2$ and variances $\sigma_1^2$ and $\sigma_2^2$ and correlation $\rho$.
I need to obtain the pdf of the transformation $||\mathbf{x}||^{-1} \mathbf{x}$: the coordinates of a variable in the unit circle.</p>
<p>In directio... | g66815 | [
0.02070525661110878,
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-0... |
<p>The application is that I want to know how $X$ maps not only to $y$, but to the variance of $y$. I think I've worked out a reasonable solution for doing so using the gamma distribution and the inverse square link, but I've got a couple of questions. The setup is as follows:
$$
y = f(X) + \epsilon\\
\epsilon = \phi... | g26032 | [
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0.08325252681970596,
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-0.... |
<p>I have 100,000 observations (9 dummy indicator variables) with 1000 positives. Logistic Regression should work fine in this case but the cutoff probability puzzles me. </p>
<p>In common literature, we choose 50% cutoff to predict 1s and 0s. I cannot do this as my model gives a maximum value of ~1%. So a thresho... | g66816 | [
-0.01816635951399803,
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0.003172... |
<p>Calculate the expected return, variance and standard deviation for the following portfolio of four stocks </p>
<p>Stock1 16.4% return</p>
<p>Stock2 -9.2% return</p>
<p>Stock3 7.9%return</p>
<p>Stock4 22.0% return </p> | g26033 | [
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<p>Let's assume there is a time series Y of length n with Y(1) being the most recent observation.</p>
<p>In MA process we plot auto-correlation function (ACF) to see how many lags to use. If we look at MA(3) process for example that implies the correlation between: </p>
<pre><code>Y(1:n-1) and Y(2:n)
Y(1:n-2) and Y(3... | g66817 | [
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0.06047675758600235,
0.07125724107027054,
0.02... |
<p>I'm getting confused about what I read about covariance. I know how to calculate covariance between two different variables, but not between two observations of the same variable. Imagine you have many observations of a variable $X$. What does this mean and how to calculate it? </p>
<p>$$
{\rm Cov}[x_i,x_j]
$$</p>... | g5376 | [
0.06135481223464012,
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0.012917613610625267,
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-... |
<p>I have a dataset of 130k internet users characterized by 4 variables describing users' number of sessions, locations visited, avg data download and session time aggregated from four months of activity.</p>
<p>Dataset is very heavy-tailed. For example third of users logged only once during four months, whereas six u... | g66818 | [
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<p>How would you explain data visualization and why it is important to a layman?</p> | g46451 | [
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<p>What algorithms are used in modern and good-quality random number generators? </p> | g46453 | [
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<p>I have 2 classification methods that I want to compare. So I ran them on the same dataset and I obtained 2 different classifications.</p>
<p>Then, I want to test if their classification is robust and how. Supposing each classification gives $n$ classes, for each method (classification):</p>
<ul>
<li><p>I created $... | g4086 | [
0.038857899606227875,
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0.05445679649710655,
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0.... |
<p>here are distributions of four samples:<img src="http://i.stack.imgur.com/LE7jO.jpg" alt=""></p>
<p>and the following is the table of data:</p>
<p><img src="http://i.stack.imgur.com/aG1Th.jpg" alt="enter image description here"></p>
<p>I would like to test: (1) if the difference between means of "Give" and "Work-... | g26041 | [
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0.03327089175581932,
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0.02459186501801014,
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0.000002036592832155293,
0.029493942856788635,... |
<p>A couple of years ago I learned about recent work in <a href="http://arxiv.org/abs/1210.7477" rel="nofollow">parallelizing slice sampling methods</a>. More recently, I have read great things about <a href="http://arxiv.org/abs/1111.4246" rel="nofollow">NUTS</a> and <a href="http://en.wikipedia.org/wiki/Hybrid_Monte_... | g26042 | [
0.042956966906785965,
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0.0362396314740181,
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0.... |
<p>I'm using a multinomial logistic regression analysis to examine deer behavioural responses to camera traps in terms of 7 predictors (both singly and their interactions). </p>
<p>I have found that the model with the lowest AIC value is season and vegetation (AIC = 1005.023). However, the AIC value for season as pred... | g49759 | [
0.0006722904508933425,
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0.021029513329267502,
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0.12215505540370941,
0.05... |
<p>I've been redirected here from another forum... </p>
<p>I have used a two sample Kolmogorov-Smirnov test to compare the distributions of two sets of data. Basically I am comparing the error distributions between two measurements when an intervention is made, to determine whether the intervention (a changing measure... | g66819 | [
0.017089616507291794,
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0.03584634140133858,
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... |
<p>I ran an ordinal logistic regression in R using the polr function on a survey analysis dataset. The responses of the dependent variable range from Poor to Excellent.
The responses to the independent variables range from 1 to 5 (1 being Poor and 5 being Excellent). I obtained the following result:</p>
<p><img src="h... | g26044 | [
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... |
<p>I am looking for a library routine that will calculate the lag 1 autocorrelation of a time series with a rolling window; meaning "slide a window of size N points along the time series, calculate the lag 1 autocorrelation for each window."</p>
<p>I have implemented an algorithm inspired by <a href="http://en.wikiped... | g66820 | [
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0.05074939504265785,
0.013986819423735142,
0.056688... |
<p>The data contains two groups and the intended comparison will be completed via independent t-test. Options that I have considered is using the entire sample's mean or one of the group means. However, I am concerned about inflating the differences between the groups. Which method is most ideal and why?</p> | g66821 | [
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0.006014855112880468,
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<p>I am currently reading the recent papers mainly written by Y. Bengio<a href="http://scholar.google.de/scholar?as_ylo=2012&q=y%20bengio&hl=en&as_sdt=0,5" rel="nofollow"> [1]</a>,<a href="http://www.iro.umontreal.ca/~lisa/bib/pub_subject/language/pointeurs/bengio+lecun-chapter2007.pdf" rel="nofollow">[2]</... | g66822 | [
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0.... |
<p>In Shane's answer to <a href="http://stats.stackexchange.com/questions/942/application-of-wavelets-to-time-series-based-anomaly-detection-algorithms">this question</a> he suggests that Hidden Markov Models can be used more successfully than wavelets for anomaly / change detection (it was a bit unclear -the topic he ... | g46455 | [
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<p>Can somebody please explain how to train a neural network in batch mode. I have a single target time series of length $N$ for a given input time series of the same length. In order to apply Hopfield network's content addressable property, I want to store this pattern of input time series. Then given a test time seri... | g15930 | [
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<p>I have a large panel-like data set: about 15,000 individuals, on average 350 time points, two dozen variables (plus some more variables we left out for context-specific reasons).
What I want to achieve is a model explaining one dependent variable $y$ by (some of) the other (i.e. explanatory) variables $x$. As a firs... | g66823 | [
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0.021185195073485374,
0.028974786400794983,
0.014306358993053436,
... |
<p>Is there any tool that can calculate the AUC value from a ROC curve if I already have true positive, true negative, false positive, false negative values. </p> | g49311 | [
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0.06270761042833328,
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<p>I have no idea how to do the following analysis for an experiment.</p>
<p>For my independent variables I have two continuous between-subject variables (personality traits scores), one categorical between-subject variable (gender), and one categorical within-subject variable (nature of the stimulus).
My dependent va... | g66824 | [
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0... |
<p>I have a survey on pricing. There are questions where there is an A and B choice where the proportions are not independent (mutually exclusive group). Here I can use a binomial distribution in Excel and can assume a probability of 50%. This will tell me with 95% confidence interval if the % selecting A is higher and... | g66825 | [
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0.0028560280334204435,
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<p>We had students take a test with 20 questions and had them indicate their confidence levels for each question. In one test format, the confidence prompt was adjacent to their test question while in the alternate format, their responses to the test question and confidence had to be indicated on a separate form. The... | g66826 | [
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<p>I am trying to standardize dataset columns for linear regression. </p>
<p>One of the columns have standard deviation = 0. </p>
<pre><code>def standardize(X):
return (X - mean(X)) / std(X)
</code></pre>
<p>So this code doesn't work. </p>
<p>Are there any tricks to solve this problem? I have tried two things<... | g26052 | [
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... |
<p>I have daily sales data from 2011 to 2013. I have to do prediction for 2014.I have used arima and exponential method to predict the daily sale, but it is not giving the better result. MAPE is around 25%. </p>
<p><code>y=ts(x,frequency=7)</code></p>
<p><code>fit <- auto.arima(y)</code></p>
<p><code>fc <- for... | g17898 | [
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-0.03770623356103897,
-0.031814899295568466,
-0.013079827651381493,
0.07087282091379166,
0.000313558557536453,
-0.02826698310673237,
0.020069342106580734,
0.12310878932476044,
0.011130833066999912,
0.13915826380252838,
-0.... |
<p>I have the vague recollection of a result that states something along the lines of </p>
<blockquote>
<p>Joint parameter estimates always lead to smaller variance than
independent parameter estimates even when the
parameters are uncorrelated.</p>
</blockquote>
<p>Does this ring a bell for anyone? What is the ... | g66827 | [
0.04331399127840996,
0.015317676588892937,
-0.0005269738612696528,
0.005076328758150339,
0.032278724014759064,
-0.0071023451164364815,
0.024512339383363724,
-0.015082312747836113,
-0.02154647558927536,
-0.004444076679646969,
-0.02836870215833187,
0.05373377352952957,
-0.0090992646291852,
0... |
<p>I'm analyzing data from an unbalanced factorial experiment both with <code>SAS</code> and <code>R</code>. Both <code>SAS</code> and <code>R</code> provide similar Type I sum of squares but their Type III sum of squares are different from each other. Below are <code>SAS</code> and <code>R</code> codes and outputs. </... | g26055 | [
0.02950255386531353,
-0.040983084589242935,
0.009343733079731464,
-0.058633916079998016,
0.036270976066589355,
-0.029812922701239586,
0.03652038797736168,
-0.03716884180903435,
0.026633191853761673,
-0.02738052047789097,
-0.0015024141175672412,
0.047056928277015686,
0.01051931083202362,
-0... |
<p>I want to see if it is possible to analyse openly available images (from google, flickr, etc.), and conclude something from them (the same way one might do this from census data but with images as data).</p>
<p>In my opinion online sources offer a wealth of data, and can easily be grouped by subject (for example: b... | g66828 | [
-0.04053748771548271,
0.04243302717804909,
-0.0030252092983573675,
-0.04912906885147095,
-0.0561414435505867,
-0.04422470182180405,
-0.002634999807924032,
0.004229535814374685,
-0.011959756724536419,
0.00939064472913742,
0.07805495709180832,
-0.032866086810827255,
0.09970313310623169,
0.04... |
<p>Is it possible to specify a variance matrix for the random effects in PROC MIXED with the only restriction that the diagonal entries are equal ? I took a look in the help and I have not found, but this seems strange because such a variance structure is rather natural in some applications. </p>
<p>(EDIT) Consider fo... | g26059 | [
-0.05030826851725578,
-0.012995797209441662,
-0.011406753212213516,
-0.05399755761027336,
0.02437235601246357,
0.007134395185858011,
0.052487753331661224,
-0.05568243935704231,
-0.015435518696904182,
-0.07553865760564804,
0.025657614693045616,
0.04554373770952225,
0.005933260545134544,
-0.... |
<p>This is, I hope, quite a simple question. Being new to the concepts and methods of Multiple Testing, I've been histogramming some of the p-values I've been computing in my genomics research. What I have been seeing is that the distribution of p-values seems to be depleted at low values. Of course, this is horrid ... | g17428 | [
0.039350513368844986,
0.03951788693666458,
-0.033375583589076996,
-0.06948237121105194,
0.014653302729129791,
-0.005309257190674543,
-0.013279767706990242,
0.04372300207614899,
-0.04096067696809769,
-0.06937456876039505,
-0.02229694463312626,
-0.018916333094239235,
0.04684863239526749,
0.0... |
<p>I am using Multiple Imputation to impute a continuous variable (<code>X</code>). I have a question regarding the generation of a new variable, starting from this imputed variable (what, in Stata jargon, would be called a <em>passive variable</em>). </p>
<p>In particular, my aim is to divide this variable <code>X</c... | g66829 | [
0.04294465109705925,
-0.06848989427089691,
-0.012212123721837997,
-0.09369534254074097,
0.0027725284453481436,
0.022712379693984985,
-0.011956807225942612,
0.022584965452551842,
-0.023196035996079445,
0.03275857865810394,
-0.023950250819325447,
-0.0012516999850049615,
-0.029912376776337624,
... |
<p>I have run a Poisson glm and I want to test for multicollinearity in my data. I have used the vif in R and obtained the following result. How can I interpret this?</p>
<pre><code> GVIF Df GVIF^(1/(2*Df))
make 1.083927 1 1.041118
cc 1.093900 1 1.045897
area 1.113460 3 1.018073
ins... | g66830 | [
0.02884548157453537,
-0.032059445977211,
-0.008361833170056343,
-0.05010754615068436,
0.03138623386621475,
-0.04520335793495178,
0.005941689480096102,
-0.0030532856471836567,
-0.0335216224193573,
-0.049686405807733536,
-0.05375014245510101,
-0.010269364342093468,
0.012360829859972,
0.00119... |
<p>Suppose I have a set of (discrete) variables, say $X_1,\dots,X_n$. Each $i$ belongs to either class A or class B. When it belongs to A the contribution is $Y_{A,i}f(X_i)$, and when it belongs to B the contribution is $Y_{B,i}g(X_i)$, so that the final outcome is $Z=\sum_{i=1}^N Y_{A,i}f(X_i) I_{\{i \in A\}} + Y_{B,i... | g66831 | [
0.010053903795778751,
-0.0717315524816513,
-0.01831263303756714,
-0.031098732724785805,
0.05581806227564812,
-0.07548720389604568,
0.06680819392204285,
-0.025600844994187355,
0.006381351500749588,
-0.01158369891345501,
-0.07467497885227203,
0.08541825413703918,
0.006549052894115448,
0.0513... |
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