question stringlengths 37 38.8k | group_id stringlengths 2 6 | sentence_embeddings listlengths 768 768 |
|---|---|---|
<p>The following concepts are baffling and would be obliged for a constructive explanation.</p>
<p>(Q1) What is the conceptual difference between (a) Kolmogorov-Sinai entropy, (b) Shannon entropy, (c) Source entropy (d) topological entropy and (e) Boltzmann entropy? </p>
<p>(Q2) What are the relationships between dif... | g63309 | [
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<p>If I have a regression model:
$$
Y = X\beta + \varepsilon
$$
where $\mathbb{V}[\varepsilon] = Id \in \mathcal{R} ^{n \times n}$ and $\mathbb{E}[\varepsilon]=(0, \ldots , 0)$,</p>
<p>when would using $\beta_{\text{OLS}}$, the ordinary least squares estimator of $\beta$, be a poor choice for an estimator?</p>
<p... | g63310 | [
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<p>Alice, Bob, and Charlie work for a company and each of them has a cell phone and a car. They drive to work and they have their cell phones with them when they show up at work. </p>
<p>The company has installed some sensors to detect the presence of the cars and cell phones. Sometimes our users use the public transp... | g63311 | [
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<p>In the project I am working we have a couple of items with different prices. Each item has description but it is possible to find items with similar description. I would like to know how can I estimate a price of a new item? I was thinking to match items based on their descriptions but it is not always useful as it ... | g20944 | [
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<p>I mainly use k-fold cross-validation for parameter tuning and model selection for prediction problems. Now, is there a standard or if not a less-known way to measure the sensitivity of the parameters over the cross-validation error, and to quantify it? Also, is it standard to look at the variability of the cross-val... | g20945 | [
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<p>I have a time series data-set that contains two separate trends(one trends has relatively lower values/ the other has higher values).If you plot it in excel, it will be very clear to see those two trends. </p>
<p>My question is: how can I separate those two different trends? I want to separate those two trends base... | g63312 | [
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<p>As we all know, profile likelihood is an effective method for the estimation of conditional parametric model. But I still don't know exactly why it works. Profile likelihood was thoroughly studied by <a href="http://www.jstor.org/stable/2242367?&Search=yes&searchText=Wong&searchText=1992&searchText=s... | g63313 | [
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<p>When reading about repeated measures ANOVA, until now 99% of examples are always with "before" and "after".</p>
<p>But if I understood correctly the point of repeated measures ANOVA is not necessarily to estimate differences <em>in time</em> but rather when one measure may be dependent on another, correct?</p>
<p>... | g98 | [
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<p>In TraMineR, seqdistmc is used to measure multichannel distances between "state" sequences. I am wondering if there is a function to measure multichannel distances between "event" sequences.</p> | g20951 | [
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<p>I am trying to analyze my data using survival CoX PH in SPSS v.19 and also attempting to make different prediction models (without and with a biomarker of interest). I am a clinician (not a biostatistician) and this is for a paper that I need for completing my Ph.D.
For my model selection I used the following method... | g20952 | [
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<p>I'd like to get clusters with a maximum inner distance threshold.</p>
<p>Now I use <code>hc <- hclust(d)</code> and <code>cutree(hc, numofclasses)</code>.</p>
<p>But I would like to use something like in python:</p>
<pre><code>>>> cl = HierarchicalClustering(data, lambda x,y: abs(x-y))
>>> cl... | g10916 | [
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<p>I'll be working with data from an intelligent tutor system similar to one studied in the <a href="http://www.sigkdd.org/kdd-cup-2010-student-performance-evaluation" rel="nofollow">KDD-Cup 2010 on student performance prediction</a> and plan to use IRT models to infer item and ability parameters. Other covariates such... | g63314 | [
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<p>I started digging a bit into the <a href="http://stat.ethz.ch/R-manual/R-patched/library/stats/html/plot.lm.html" rel="nofollow">plot.lm</a> function, this function gives six plots for lm, they are:</p>
<ol>
<li>a plot of residuals against fitted values</li>
<li>a Scale-Location plot of sqrt(| residuals |) against ... | g20957 | [
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<p>Given a sequence of inputs, I need to determine whether this sequence has a certain desired property. The property can only be true or false, that is, there are only two possible classes that a sequence can belong to.</p>
<p>The exact relationship between the sequence and the property is unclear, but I believe it i... | g40238 | [
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<p>I have a model $$Y=\beta_0 + \beta_1 x_1 + \beta_2x_2 +\epsilon$$</p>
<p>I would like the minimum variance unbiased estimate of $\gamma=\beta_1 + \beta_2$. Assuming the Gauss Markov conditions hold, but $x_1$ and $x_2$ are correlated, is there a more efficient way to estimate $\gamma$ than running OLS and adding ... | g20958 | [
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<p>I'm kind of new to datamining/machine learning/etc. and have been reading about a couple ways to combine multiple models and runs of the same model to improve predictions. </p>
<p>My impression from reading a couple papers (which are often interesting and great on theory and greek letters but short on code and act... | g20959 | [
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<p>I have about 30000 book names assigned to 6 categories, and I want to build scalable and accurate classifiers. So far I have only been able to use Naive Baye's and <a href="http://www.csie.ntu.edu.tw/~cjlin/liblinear/" rel="nofollow">LibLINEAR</a> classifiers and they both give me an (almost) identical precision an... | g20960 | [
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<p>I know that there are various posts regarding variable selection but I am asking something particular. With respect to the question that I posted today in the following link:</p>
<p><a href="http://stats.stackexchange.com/questions/11420/low-accuracy-in-out-of-time-validation">Low accuracy in out of time validation... | g63315 | [
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<p>Does anyone use the $L_1$ or $L_.5$ metrics for clustering, rather than $L_2$ ?<br>
Aggarwal et al.,
<a href="http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.23.7409&rep=rep1&type=pdf" rel="nofollow">On the surprising behavior of distance metrics in high dimensional space</a>
said (in 2001) that</p>... | g20962 | [
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<p>I am interested in fitting a Bayesian Two Factor ANOVA in BUGS or by utilizing some R package. Unfortunately I am having a hard time finding resources on this topic. Any suggestions? Even an article describing the approach would be helpful.</p> | g63316 | [
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<p>Suppose $x_{1}, x_{2} \dots x_{N}$ are gaussian RVs with variance $S$ and mean $1$. What is the density function of</p>
<p>$$\frac{ |\sum_{n=1}^{N}x_{n}|^{2}}{\sum_{n=1}^{N}|x_{n}|^{2}}\text{?}$$</p> | g20964 | [
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<p>I came across a paper mentioning sample size calculation for 10% shift, 20% shift and 50% shift. I understand the SSC concept but what exactly is 10% shift and 20% shift.? So lets say for example if have a mean difference of 8787 , and SD of 102 , how do i calculate Sapmple size for this at 10% shift, 20% shift and ... | g63317 | [
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<p><img src="http://i.stack.imgur.com/gMBYg.gif" alt="[Here is an image for details!](https://onlinecourses.science.psu.edu/stat504/sites/onlinecourses.science.psu.edu.stat504/files/lesson07/crab_r_output_02.gif)"></p>
<p>Disregarding "Deviance" in the image, the output of multiple regression analysis in R looks prett... | g63318 | [
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<p>I'd like to ask a question here that I've also asked on Biostar (stackexchange) and someone there forwarded me to this website. I was wondering how I could perform a Bray Curtis similarity clustering in R in which I show the similarity percentages on an inverted Y-axis and all tree nodes ending at 100% as I've shown... | g63319 | [
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<p>Suppose we are trying to estimate the quantity $\theta$ and we have that the estimator $\hat\theta_n$. Suppose it is efficient, i.e. is variance is the smallest among certain class of other possible estimators of $\theta$, say that this class is a class of unbiased estimators. </p>
<p>Efficient estimators are natur... | g63320 | [
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<p><strong>Input</strong></p>
<pre><code>1 0
7 77
6 66
</code></pre>
<p><strong>Expected Output</strong></p>
<pre><code>7 66
</code></pre>
<p><strong>Solution in Google Spreadsheet</strong></p>
<pre><code>= arrayformula(if(B2:C2,B3:C3,B4:C4))
</code></pre>
<p>How to do that in Excel?</p>
<p>Please, add l... | g20967 | [
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<p>I want to measure the entropy/ information density/ pattern-likeness of a two-dimensional binary matrix. Let me show some pictures for clarification:</p>
<p>This display should have a rather high entropy:</p>
<p>A)</p>
<p><img src="http://i.stack.imgur.com/Fxy5j.jpg" alt="enter image description here"></p>
<p>Th... | g258 | [
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<p>I have a set of data of 2 variates. I have generated correlation matrix between the variates. Using <code>copula</code> package of R, I computed t-copula using correlation matrix. I used the following technique for that:</p>
<ol>
<li>With the help of correlation matrix for example let it be <code>corr_mat</code>, I... | g63321 | [
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<p>I am estimating a mixed logit model with hierarchical Bayes procedures to deal with my categorical data.
I am wondering if I'm representing the data correctly.</p>
<p>The data comes from experiments where participants are shown constructed images and need to identify if the image is constructed from information of ... | g63322 | [
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<p>What is the relationship between a Nonhomogeneous Poisson process and a process that has heavy tail distribution for its inter arrival times?</p>
<p>Any pointer to a resource that can shed some light on this question would be hugely appreciated</p> | g63323 | [
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<h3>Context</h3>
<p>I have a survey of 16 questions, each with four possible responses. The purpose of the survey is to measure the respondent's propensity towards four categories (which we will denote A, B, C, D). Each of the four responses per question are representative of an aspect of the four categories, A, B, C,... | g63324 | [
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<p>Just wonder, is there any data analysis/ statistic/ data mining work that are available on freelance basis?</p>
<p>This could be subjective and argumentative, which is why I put it as CW. </p> | g63325 | [
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<p>From <a href="http://en.wikipedia.org/wiki/Non-parametric_statistics" rel="nofollow">Wikipedia</a></p>
<blockquote>
<p>The first meaning of non-parametric covers techniques that do not rely on data belonging to any particular distribution. These include, among others:</p>
<ul>
<li>distribution free methods... | g63326 | [
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<p>How can I calculate the sensitivity and specificity (or analogous measures) of a continuous diagnostic test in predicting a continuous outcome (e.g., blood pressure) without dichotomizing the outcome? Any ideas?</p>
<p>It appears that researchers have done this using mixed effects modeling (see link below), but I'... | g63327 | [
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<p>I have a database of events (i.e. a variable of dates) and associated covariates.</p>
<p>The events are generated by the non-stationary Poisson process with parameter being an unknown (but possibly linear) function of some covariates.</p>
<p>I think the NHPoisson package exists just for this purpose; but after 15 ... | g63328 | [
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<p>I am trying to predict (binary) memory for pictures based on two continuous fixed effects: memorability and clutter. Using a mixed effects model, I found that both effects predict memory and including both in a model is better than either on their own.</p>
<p>However, memorability and clutter are highly correlated.... | g63329 | [
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<p>I have a bunch of web page response time data, and I'm recording dispersion stats--both variance and quartile--on an hourly basis.</p>
<p>Are there good ways to roll this up into larger time scales (e.g., daily, weekly), as opposed to having to reprocess the original dataset? I understand that in the initial hourly... | g63330 | [
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<p>I'm following a course in econometrics where we have established that for a linear regression model
$$y_i=x_i'\beta+\varepsilon_i$$</p>
<p>If $1/N \sum_{i=1}^N x_i x_i'$ converges to a nonsingular matrix and $E[x_i \varepsilon_i]=0$ OLS will be consistent . </p>
<p>What I would like to know if it can happen that O... | g49673 | [
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<p>Is there a situation in which the mean of a Y variable is not 0 (e.g. not standardized), but we would still fit a regression model without intercept?</p>
<p>It would yield a worse fitting model, so is there a scenario in which you would omit adding an intercept with a good reason? </p> | g63331 | [
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<p>I am using panel data set and want to know which model I should use, fixed effect or random effect. On which basis is this selection done? When I asked my teacher he told me that model is selected on the base of Hausman specification test .</p>
<p>I am using the panel data for measuring the bilateral trade between ... | g63332 | [
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<p>I am using parallel process growth mixture modeling to estimate bidirectional longitudinal dynamics between pain (0-100 theoretical range of values) and sleep measures (0-20 theoretical range of values). Conceptually speaking if I log transform both of these raw measures and then regress their latent variables (inte... | g63333 | [
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<p>I am working on a study that examines word processing with native and non-native speakers. We have three independent variables: Groups (NSs and NNS), word types (five conditions), and word relatedness (related and unrelated words), and one dependent variable; Reaction Time.
I have successfully ran linear mixed effe... | g20971 | [
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<p><em>Hi, this is the first time I am posting a question here so I apologize if my questions are not written in the proper manner and corrections will be welcomed</em>. </p>
<p>I have a dataset in which each instance is defined by a cluster (C) and two more fields: trials and successes forming the following instance ... | g63334 | [
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<p>I'm trying to calculate partitioned sum of squares in a linear regression. In the first model, there are two predictors. In the second model, one of these predictors in removed. In the model with two predictors versus the model with one predictor, I have calculated the difference in regression sum of squares to be 2... | g63335 | [
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<p>I've got a question concerning leave-one-subject-out cross-validation of a classifier and correct outlier handling in this case.</p>
<p>Let's suppose I've got 5 subjects. Within each subject the features are standardised (mean subtracted and divided by standard deviation) missing values or outliers are represented ... | g20974 | [
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<p>Consider a linear unobserved effects model of the type:
$$y_{it} = X_{it}\beta + c_{i} + e_{it}$$
where $c$ is an unobserved but time-invariant characteristic and $e$ is an error, $i$ and $t$ index individual observations and time, respectively. The typical approach in a fixed effects (FE) regression would be to rem... | g63336 | [
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<p>I am doing some research about forecasting time series of probability density functions. We are aiming to forecast a PDF given historically observed (usually, estimated) PDF. The forecasting method we are developing performs pretty well in simulation studies. </p>
<p>However, I need an numerical example from real a... | g63337 | [
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<p>I want to test a sample correlation $r$ for significance, using p-values, that is </p>
<p>$H_0: \rho = 0, \; H_1: \rho \neq 0.$ </p>
<p>I have understood that I can use Fisher's z-transform to calculate this by</p>
<p>$z_{obs}= \displaystyle\frac{\sqrt{n-3}}{2}\ln\left(\displaystyle\frac{1+r}{1-r}\right)$</p>
<p... | g63338 | [
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<p>I am studying different point estimate methods and read that when using MAP vs ML estimates, when we use a "uniform prior", the estimates are identical. Can somebody explain what a "uniform" prior is and give some (simple) examples of when the MAP and ML estimators would be the same?</p> | g63339 | [
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<p>I'd like to do an analysis to identify possible patterns in users demands against users demographics. I won't go into the details regarding the analysis, my question is mainly about the data cleaning/preparation.</p>
<p>My data is coming from 2 tables in MySQL:</p>
<ul>
<li>user table (user_id, list of demographic... | g20976 | [
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<p>I have collected reproductive data from 393 trees from 51 provenances across the distribution of my study species. At each of these sites I have also recorded the level of fragmentation for each of the collected trees (1-4, where 1 is single paddock tree and 4 is an closed canopy forest). I want to test the influenc... | g63340 | [
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<p>I have 2 different variates W,X. I want to compute Gumbel copula for these variates. I followed following steps for the same:
1. To compute kendall's tau I used R's package Kendall. From kendall's tau I computed gumbel parameter(alpha) as alpha=1/(1-tau).</p>
<ol>
<li><p>Then I computed gumbel copula using R's pack... | g63341 | [
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<p>I am working with time series values which are all in the closed interval [0, 1]; these values represent relative frequencies, i.e., empirical probabilities. I would like to create a model such that all forecasted values are within [0, 1], but it would also be fine if the model's output was strictly within the open ... | g63342 | [
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<p>The <code>ordLORgee</code> command from the <code>multgee</code> package in R has an argument LORstr. With this argument the user can specify the marginalized local odds ratio structure.</p>
<p>What is a marginalized local odds ratio structure?</p>
<p>How do I determine which marginalized local odds ratio structur... | g63343 | [
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<p>I am conducting a simulation study, which involves several clustering methods such as model-based clustering method (MBCM). However, there is a big problem I find that MBCM runs so slowly (might be due to the EM algorithm). I have tried my best to avoid for loop in my simulation setting but it still takes me foreve... | g20982 | [
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<p>Say the observations are $x_i$ and the states are $y_i$ in a sequential model.</p>
<p>I understand that particle filtering works by generating "particles" from $p(y_i | x_1,\ldots,x_i)$ for approximating $p(y_{i+1} | x_1,\ldots,x_{i+1})$.</p>
<p>How do we decide on how many "particles" to use as we go along on the... | g63344 | [
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<p>I have a panel cost data with some zero values (not missing values but rounded to 0). How should I handle zeros when I use SAS Proc Glimmix with Gamma distribution? Maybe change zero to very small values? Or is there an option for it (which I couldn't find) in PROC GLIMMIX?</p>
<p>Janne</p> | g40283 | [
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<p>I have been reading that when the underlying error is distributed normally, then minimising the sum of squared difference between the observed data and the model is the appropriate cost function to do the model fitting. However, I am having trouble understanding why that is the case.</p>
<p>I was wondering if there... | g63345 | [
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<p>I am trying to understand ANOVA. In one-way ANOVA to test equality of mean of several population groups, each group has a normal distribution with the same variance. I wonder if the common variance of each group is known and used somewhere or unknown and estimated from samples in ANOVA? Thanks and regards!</p> | g63346 | [
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<p>Say I have an $n \times n$ covariance matrix for a sample set of $n$ random variables. Is there any meaning if the sum of the rows of this matrix? Is it a meaningful measurement of the contribution of each random variable to the variance of sum of the random variables?</p> | g63347 | [
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<p>I'm currently analysing some EEG data using a repeated measures general linear model, and I've run into a problem. I have three within-subject factors; Scalp area (3), condition (2) and word (2). When I run a three-way analysis I get mean values for Word (separated by condition) which don't match up to the means I'v... | g20990 | [
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... |
<p>I have completed a demo of a naive Bayes classifier for predicting whether an SMS message is spam or ham. </p>
<p>My question is, how can I use this in a practical manner? It appears I would have to completely retrain the classifier every time there is a new message.</p>
<p>Ideally, I would like to simply pass i... | g20991 | [
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0.006326728966087103,
-0.029172031208872795,
-0.033773794770240784,
0.06995046883821487,
0.06676393002271652,
0.04... |
<p>I have 2 groups of patients and I'm looking at what percentage were discharged from the hospital at different time points after surgery.</p>
<pre><code> Day 1 Day 2 Day 3 Day 4
Group 1 12% 10% 25% 12%
Group 2 50% 20% 20% 15%
</code></pre>
<p>What i... | g20992 | [
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0.0007160558016039431,
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0.02286271564662456... |
<p>I am currently bothered on how to statistically analyze my simple data as shown below. </p>
<pre><code>Date Spatial Features
1 2 3 4 5 6
----------------------------------------------
1988 0.7784 0.8310 0.8726 0.9307 0.9189 0.8814
1998 0.8956 0.9036 0.9368 0.9575 0.92... | g20994 | [
0.029284970834851265,
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0.06057651340961456,
0.01879091188311577,
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0.017161639407277107,
0.0020619418937712908,
0.017960824072360992,
0.05074497312307358,
-0.... |
<p>We sometimes use spectral density plot to analyze periodicity in time series. Normally we analyze the plot by visual inspection and then try to draw a conclusion about the periodicity. But has the statisticians developed any test to check whether any spikes in the plot are statistically different from white noise? H... | g63348 | [
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0.04386482015252113,
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0.03269928693771362,
0.05227729305624962,
0.03759928420186043,
0.05242861062288284,
0.00... |
<p>In machine learning and in statistics there exist plenty of measures which estimate the performance of a predictive model. For example, classification accuracy, area under ROC curve ... for classification or $R^2$ for regression models.</p>
<p>Is there any generalisation of such measures for multiple dependent vari... | g63349 | [
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<p>I have a binary dependent variable, say food security status, where 0 = <em>food insecure</em> and 1 = <em>food secure</em>, and this response variable is recorded for two categories of households, <em>small farmers</em> and <em>land less rural house holds</em>. Both these household categories may have food secure o... | g63350 | [
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0.... |
<p>I am wondering if somebody has used or has any reference to point as to how a neural network in conjunction with PROC logistic can be used in sas. A code would be an ideal thing for me but if unavailable, if somebody can pass me a link as to how can I benefit myself from using neural network alongside logistic ?</p> | g63351 | [
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0... |
<p>Does the Pearson's correlation estimator require no <a href="http://www.psychwiki.com/wiki/Detecting_Outliers_-_Multivariate" rel="nofollow">bivariate outliers</a>, or no outliers in each of two individual vectors of data? The answer will impact on how I winsorize outliers before calculating my Pearson estimate. </p... | g37537 | [
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... |
<p>I have 20 questions, each divided in 6 Likert scale items (1-7), representing 6 different values like Success, Oportunity, etc. The sample is rather small, 42 cases, and the distribution is not normal. </p>
<p>Basically, I want to compare responses to values between individuals in certain groups consisting of 4-5 i... | g20995 | [
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0.035580895841121674,
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-0.01652965880930423... |
<p>The probability of a sequence of n independent Bernoulli trials can be easily expressed as
$$p(x_1,...,x_n|p_1,...,p_n)=\prod_{i=1}^np_i^{x_i}(1-p_i)^{1-x_i}$$
but what if the trials are not independent? </p>
<p>How would one express the probability to capture the dependence?</p> | g49538 | [
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0.05... |
<p>$$Y_t = a + bX_{1,t} + cX_{2,t} + dX_{3,t} + e_t$$</p>
<p>A high $R^2$ in $X_{1,t} = \alpha + \beta X_{2,t} + \gamma X_{3,t} + \varepsilon_t$ will always result in a higher standard error of the $b$ estimator, <em>all else held equal</em>. This is an example of the multicollinearity problem. It <a href="http://stat... | g20997 | [
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... |
<p>I'm working on a little project, which is in early development stage right now. What I'm trying to figure out is how do I generate random music, especially notes. By googling I've only managed to find <em>ransom</em> note generator and lots of random music, where word random has nothing to do with definition of rand... | g39620 | [
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<p>In general, and more specifically for Bernoulli mixture model (aka Latent Class Analysis).</p> | g63352 | [
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0.0386... |
<p>I would like to make/explore several alternative formulations of random forest (<a href="http://www.stat.berkeley.edu/~breiman/RandomForests/cc_home.htm">link</a>) and am looking for the current state of the science for evaluating performance.</p>
<p>In the reference file Leo provides "microarray", "DNA", "glass", ... | g63353 | [
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<p>From <a href="https://en.wikipedia.org/wiki/Omnibus_test" rel="nofollow">Wikipedia</a></p>
<blockquote>
<p>Omnibus tests ... test whether <strong>the explained variance</strong> in a set of
data is significantly greater than <strong>the unexplained variance</strong>,
overall. </p>
<p>...</p>
<p>Omni... | g63354 | [
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0... |
<p>I'm looking for a Python module that performs a change-point analysis on a time-series. There are a number of different algorithms and I'd like to explore the efficacy of some of them without having to hand-roll each of the algorithms.</p>
<p>Ideally I'd like some modules like the <a href="http://cran.r-project.org... | g63355 | [
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<p>I'm looking over some work performed by a consultancy and I'm unsure whether the standard error formula they have used is correct, and the subsequent conclusions they have drawn are erroneous.</p>
<p>They have provided a Standard Error between the difference in observed claim frequencies and modelled claim frequenc... | g21001 | [
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<p>I was wondering if there wasn't some better way to get to the bottom of this question I had regarding the chances of reaching a certain threshold of guessing numbers correctly over a series of trials. This isn't my specialty, so would appreciate answers that are like you were talking to a 5 year old or at least goo... | g21003 | [
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<p>Can you give some real-life examples of time series for which a moving average process of order $q$, i.e.
$$
y_t = \sum_{i=1}^q \theta_i \varepsilon_{t-i} + \varepsilon_t, \text{ where } \varepsilon_t \sim \mathcal{N}(0, \sigma^2)
$$
has some <em>a priori</em> reason for being a good model? At least for me, autore... | g63356 | [
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... |
<p>Two running teams take part in competitions on the same course, but their competitions differ because of the number of teams entered in each competition.</p>
<p>Results are based solely on position - times are not taken.</p>
<p>Competition 1 has 7 teams of 8 runners
Each team enters 2 of its runners in each of 4 r... | g21005 | [
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<p>I'm doing a research and using random variables to model a random process. I'm defining a Bernoulli random variable as a product of several other Bernoulli variables (three or more). So, I have the following as the expectation: </p>
<p>$E[X_1]=E[X_2X_3X_4]$ </p>
<p>I cannot assume the independence of the variables... | g43280 | [
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<p>Let's say in machine learning the test cases are biased towards one or more options.</p>
<p>For example when there are 100 (just an example) test cases in total and every test case has a color to be suggested:</p>
<p>60 => blue<br>
30 => green<br>
9 => red<br>
1 => yellow </p>
<p>Most machine learning techniqu... | g11235 | [
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<p>I have performed a mixed design ANOVA with time (pre-post) and group (treatment vs control) as variables. I'm wondering if it's sensible to use <em>between subjects difference adjusted CIs</em> (from Baguley, 2012) in the interaction plot below. What I want to emphasize is the group difference at post-test (and of c... | g40299 | [
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<p>I've a county/district that I've divided into ~300 grids that are 15km^2 in size attributed with various habitat and economic variables that have been summarized and standardized. I then have 2 types of data 1) presence/absence of leopard caused human deaths and 2) counts of those human deaths. Of the 300 grids 80 ... | g21009 | [
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<p>I've got a question concerning a negbin regression: suppose that you have the following commands </p>
<pre><code>require(MASS)
attach(cars)
mod.NB<-glm.nb(dist~speed)
summary(mod.NB)
detach(cars)
</code></pre>
<p>(note that cars is a dataset which is available in R) and don't care if this model makes sense. Wha... | g40301 | [
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<p>I have developed a system to trace the outlines of (images of) objects. Now I want to test whether two independent traces represent a common feature.</p>
<p>Imagine two people (or machines) tracing the outline of a feature in an image, recording it as sequence of vertices. Inaccuracies in recognizing the feature bo... | g63357 | [
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<p>I've a facebook users dataset in which each user has a "huge" set of attribute, i.e about 220 attributes like age, hometown, religion, and a set of facebook liked pages to store the users tastes.</p>
<p>Now I need an automatic tool (i've no time to develop an entire framework) to select only the relevant features i... | g11238 | [
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<p>I usually use the <code>plot(lm())</code> or <code>plot(glm())</code> (combined with <code>par(mfrow=c(2,2)</code>) to analyze residuals. Unfortunately this is not possible whenn estimating a <code>tobit()</code> (package <a href="http://cran.r-project.org/web/packages/AER/index.html" rel="nofollow">AER</a>) or <cod... | g21013 | [
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<p>Suppose we have the following probabilistic graphical model: </p>
<p>$L \rightarrow X, L \rightarrow Y, F \rightarrow Y, X \rightarrow D, Y \rightarrow D$. </p>
<p>That is, the joint is: $P(D,X,Y,L,F) = P(D|X,Y)P(X|L)P(Y|L,F)P(L)P(F)$. </p>
<p>Here $L,F,D$ are discrete, $X,Y$ are continuous random variables (havi... | g21014 | [
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<p>Can you suggest some good movies which involve math, probabilities etc? One example is <a href="http://en.wikipedia.org/wiki/21_%282008_film%29">21</a>. I would also be interested in movies that involve algorithms (e.g. text decryption). In general "geeky" movies with famous scientific theories but no science fictio... | g63358 | [
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<p>I have started learning classification in machine learning. I face two terminologies, one is "single class classification" and a the other is "binary class classification".</p>
<p>I am confused about when to use single class classification and when to use binary class classification. My question mainly concentrates... | g63359 | [
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0.056834... |
<p>I'm trying to compute the probability of an extreme event, using extreme value theory on my data. One of the typical problems with this kind of computations is the lack of sufficient data, which also occurs in my case. More specifically I would like to become a yearly occurance rate of a certain event, but I only ha... | g63360 | [
0.07017961144447327,
0.02592972107231617,
0.010523085482418537,
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0.02249310351908207,
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0.0... |
<p>How can I show that a random walk ($y$ follows a random walk) is not covariance stationary? I tried to work on the formula below (with no results) Could you give me just a hint on how to proceed please?</p>
<p>$$Cov(y_{t+h},y_t)=E(y_{t+h}\times y_t)-E(y_t)E(y_{t+h})$$</p>
<p>Is this approach right?</p>
<p>Importa... | g21017 | [
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0.... |
<p>I have a dataset with continuous data (i.e. several time points) from an experiment with 2 treatments (i.e. independent variables) and 2 replicate measurements per time point and treatment.
What is the right statistical analysis to apply? I tried MANOVA and PERMANOVA for distinct time points, but using this approach... | g63361 | [
0.013000080361962318,
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-0.01424132287502288... |
<p>I used <code>kmeans</code> command on my data-frame (as suggested in "R and Data Mining: Examples and Case studies"). Now my data is clustered into x number of cluster.<br>
What they don't tell you in this book is what to do next.<br>
How can I get <code>characteristics</code> specific for <code>cluster 1</code>.<br... | g63362 | [
0.015142736956477165,
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0.004017216619104147,
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0.02486199513077736,
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0.08090721815824509,
0.08584166318178177,
0.011... |
<p>I would like to code a kmeans clustering in python using pandas and scikit learn. In order to select the good k, I would like to code the Gap Statistic from Tibshirani and al 2001 (<a href="http://www.stanford.edu/~hastie/Papers/gap.pdf">pdf</a>).</p>
<p>I would like to know if I could use <a href="http://scikit-le... | g63363 | [
-0.028585277497768402,
-0.021078065037727356,
-0.002358743455260992,
-0.0486784502863884,
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0.0004910325515083969,
0.0571654848754406,
-0... |
<p>I am trying to test a hypothesis I have about consolidation in the real-world market for a certain machine. (My apologies in advance for obfuscating a bit here, but some of the data is proprietary and may not be redistributed.)</p>
<p>1) The market has two components: new machines sold and existing machines in use.... | g40304 | [
-0.013813055120408535,
0.0013907385291531682,
-0.0037498422898352146,
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0.07544884830713272,
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0.030406102538108826,
0.033692702651023865,
0.011036243289709091,
0.05793320760130882... |
<p>I am trying to expand my knowledge of statistics. I come from a physical sciences background with a "recipe based" approach to statistical testing, where we say <em>is it continuous, is it normally distributed -- OLS regression</em>.</p>
<p>In my reading I have come across the terms: random effects model, fixed eff... | g40306 | [
0.020307237282395363,
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-0.... |
<p>I came by several posts and papers claiming that pruning trees in a "bagging" ensemble of trees is not needed (see <a href="http://stats.stackexchange.com/questions/36298/why-is-pruning-not-needed-for-random-forest-trees">1</a>).</p>
<p>However, is it necessarily (or at least in some known cases) damaging to perfor... | g14410 | [
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0.01638425886631012,
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0.06... |
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