question stringlengths 37 38.8k | group_id stringlengths 2 6 | sentence_embeddings listlengths 768 768 |
|---|---|---|
<p>Simple question: What is the update equation of a $x_i$ in a Gibbs sampling update, $p(x_i | x_{-i})$, if I have the Model:</p>
<p>$\theta$ $|$ $\alpha \sim Dir(\alpha)$</p>
<p>$X_i$ $|$ $\theta \sim Discrete(\theta), i = 1, 2, 3$</p>
<p>Is it the predictive distribution of a dirichlet multinomial?</p>
<p>$\fra... | g58932 | [
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<p>I know this question has been asked before but I am looking at a specific stats book not just a grad level book. I am looking at stats book that goes beyond an undergrad probability and statistics course and goes into things like QQ plot, Wilcoxon test that is useful for data analysis. I have looked into "All of non... | g58933 | [
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<p>I am analyzing a panel dataset with Stata 13.</p>
<p>To decide whether I should use a random-effect or fixed-effect estimator (in Stata language, <code>xtreg, re</code> VS <code>xtreg, fe</code>), I implement the Sargan-Hansen test of over-identifying restrictions, which is based on the artificial regression appro... | g58934 | [
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<p>Some attribute $x$ of 17 individuals was recorded repeatedly on 6 time points using a Likert scale with 7 distractors. Which statistical test(s) can I apply to check whether the changes along the 6 time points were significant?</p>
<pre><code>set.seed( 123 )
x <- matrix( sample( 1:7, 17*6, repl=T ),
nrow = 17... | g14245 | [
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<p>Please suggest a non parametric test that is analogous to the MANOVA. I have 7 nutrient intakes of men and women. How do I test if their intakes are equal?</p> | g58935 | [
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<p>I have two sets A and B each containing N elements and want to show that the true mean of A is less than that of B with certain degree of confidence. (Specifically, the sets represents items of "yes" and "no", and I want to show that one set contain more yeses than the other.) I do not know the true mean of either s... | g14248 | [
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<p>I have done a regression model where i determine the number of cubes (independent variable) based on the amount of units i started with for each product type (dependent variables, <code>X1, X2, X3, X4, X6, X9, X10, X15</code>). But i would like a second opinion on the results, because the tests for heteroscedasticit... | g58936 | [
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<p>I've studied a large amount of Probability & Statistics, but I'm embarrassed to say I've forgotten too much of it.</p>
<p>Would appreciate any pointers anyone has about this:</p>
<p>I have a set of about 360 time series, call them "S_all".</p>
<p>I would like to be able at time t, to predict which time series... | g58937 | [
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<p>I would like to learn about the Markovitz theory because I am going to interview at a financial firm that uses variants of it extensively. </p>
<p>I am looking for a resource to learn about the intuition and optimization models behind Markovitz modern portfolio theorem. Any pointer to a book or webpage would greatl... | g58938 | [
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<p>I was using Eviews, and I noticed that there is 'dynamic forecast' and 'static forecast' in the option. But I don't know what is the difference, would any one tell what are they? But I know that both are one-step ahead forecast.</p> | g37829 | [
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<p>Anyone can suggest me a nonparametric version of the intraclass correlation coefficient (ICC)? My model have the following details: two-way random effects model, consistency, average ratings as unit. I am using irr R-cran package.</p>
<p>thank you</p> | g14255 | [
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<p>I've got a set of input-output vector pairs, and I want to find a function that approximates the output vectors from the input vectors. Specifically, I want a <em>matrix</em> by which to multiply an input vector such that I get a good approximation for the output.</p>
<p>I guess <em>linear</em> regression is not wh... | g14258 | [
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<p>This is clearly just a matter of definition or convention, and of almost no practical importance. If $\alpha$ is set to its traditional value of 0.05, is a $p$ value of 0.0500000000000... considered to be statistically significant or not? Is the rule to define statistical significance usually considered to be $p <... | g49525 | [
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<p>I was reading this wiki <a href="http://en.wikipedia.org/wiki/Kriging" rel="nofollow">article</a> related to ordinary kriging where they calculated the weights like this </p>
<p>I know that covariance from the covariogram and semivariance from the semivariogram are different things. However, when they generated the... | g58939 | [
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<p>It is well-known, especially in natural language processing, that machine learning should proceed in two steps, a training step and an evaluation step, and they should use different data. Why is this? Intuitively, this process helps avoid overfitting the data, but I fail to see a (information-theoretic) reason this... | g58940 | [
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<p>I need to train a linear classifier on my laptop with hundreds of thousands of data points and about ten thousand features. What are my options? What is the state of the art for this type of problem?</p>
<p>It seems like stochastic gradient descent is promising direction, and my sense is that this is state of the a... | g58941 | [
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<ol>
<li><p>To perform calibration of a Cox regression model (i.e. assessing for the agreement between the predicted and the observed outcome), what is the best method to present the accuracy of the model in predicting the actual event? </p></li>
<li><p>As far as I understand, we can calculate the actual outcome probab... | g58942 | [
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<p>I have a web application which allows users to take questions. Ultimately I store the following data:</p>
<p>1) Questions attempted by each user</p>
<p>2) Questions correct by each user</p>
<p>3) Avg. Time per user for correct answers. </p>
<p>I need to calculate a score for each user based on their average time... | g58943 | [
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<p>I'm working on a project using logistic regression to predict student retention. The data were collected through three self-report instruments. We are trying to find out which predictors are powerful enough to predict the at-risk students. I came across some articles saying a balanced sample (50% stay, 50% dropouts)... | g58944 | [
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<p>I need to solve the following problem:</p>
<p>Given $n$ yes/no experiments, and a success probability $p$, at least how many successes $k$ can I expect (say, with a 'confidence' of $c=95\%$ or more)?</p>
<p>Another way to put it is: I want to be 95% sure to have at least $k$ successes.
Everything is given, and I a... | g58945 | [
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<p>I asked the following question on stack overflow yesterday:
<a href="http://stackoverflow.com/questions/18085026/negative-binomial-function-in-r">Negative binomial function in R</a></p>
<p>Reading comment 2, I understand that I cannot use a negative binomial modeling approach (a Poisson model works, but I suspect t... | g58946 | [
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<p>I have approximately 20% data missing in my sample (n=3215). I aim to assess the pre-post differences on a psychometric scale. Especially post measures are missing because of follow-up issues. What to do? Should I exclude cases listwise/pairwise or replace missings with series mean or linear interpolation?</p>
<p>I... | g14265 | [
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<p>I ran an OLS regression model on data set with 5 independent variables. The independent variables and dependent variable are both continuous and are linearly related. The R Square is about 99.3%. But when I run the same using random forest in R my result is '% Var explained: 88.42'. Why would random forest result be... | g14266 | [
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<p>I am doing some descriptive statistics of daily returns on stock indexes. I.e. if $P_1$ and $P_2$ are the levels of the index on day 1 and day 2, respectively, then $log_e (\frac{P_2}{P_1})$ is the return I'm using (completely standard in literature). </p>
<p>So the kurtosis is huge in some of these. I'm looking at... | g37832 | [
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<p>After running iterations of <code>lm()</code> in R, I am now stuck with which components of the model's output to present and how to present them. I know that the $R^{2}$ value, coefficients plot and intercept are of central importance. Is there any free resource which shows: how to interpret output, and then visual... | g11834 | [
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<p>I'm working on the following missing data problem to learn more about stats, probability, and machine learning, but I'm not really making progress solving it:</p>
<p>I have a group of unordered, non-unique integers. Because of sampling error, there is a small probability (say <= 5%) that one or more integers is ... | g14270 | [
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<p>I came across a <a href="http://www.kdnuggets.com/data_mining_course/assignments/final-project.html" rel="nofollow">data mining course project</a> online.</p>
<p>The data is of samples with 7000 features as genes. Each gene is associated with a value. Some of the values are negative. The data looks like in this way... | g8091 | [
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<p>I have two treatments (rodent poisoning quadrats ($n=5$) and non poisoning quadrats ($n=5$)) and for each treatment I survey the number of individually identified invertebrates appearing across time after $6$, $15$, $30$ and $42$ months. My set of data is a number of cumulated new invertebrates appearing for the tw... | g14272 | [
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<p>I am trying to implement the ideas in this paper: <a href="http://www.sciencedirect.com/science/article/pii/S0925231212003396" rel="nofollow">http://www.sciencedirect.com/science/article/pii/S0925231212003396</a>. </p>
<p>This requires me to be able to remove individual trees from the forest and reclassify my train... | g58947 | [
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<p>In putting a binary 1/0 predictive algorithm into production, what are the consequences where only the positive (1) predictions are checked, meaning only true or false positives are detected, and then fed back into training the model? Will that bias the algorithm in any way so that it progressively gets worse and wo... | g14273 | [
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<p>What would be the optimal (Bayesian?) solution for
fitting a model $f(x)$ to data $h$, given the following assumptions:</p>
<ul>
<li>$h$ is a vector with $N$ elements</li>
<li>$h$ has Gaussian noise with known covariance $\sigma_h I$</li>
<li>$x$ is known to have an a-priori Gaussian distribution, with covariance $... | g14275 | [
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0.028620876371860504,... |
<p>In article <a href="http://www.csie.ntu.edu.tw/~cjlin/papers/libsvm.pdf" rel="nofollow">LIBSVM: A Library for Support Vector Machines</a> there is written, than C-SVC uses loss function:</p>
<p>$$ \frac{1}{2}w^Tw+C\sum\limits_{i=1}^l\xi_i$$</p>
<p>OK, I know, what is $w^Tw$. </p>
<p>But what is $\xi_i$? I know, ... | g58948 | [
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<p>Let $U,V,W$ are independent random variables with $\mathrm{Uniform}(0,1)$ distribution. I am trying to find the probability that $Ux^{2}+Vx+W$ has real roots, that is, $P(V^{2}-4UW> 0)$
I have solved this question using double integral but how to do this using triple integral.
My Approach:
I started with cdf:
$P(... | g14276 | [
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<p>How would one estimate the maximum given population size, a few moments, and perhaps some additional assumption on the distribution?</p>
<p>Something like "I'm going to do $N_s≫1$ measurements out of population of size $N_p≫N_s$; will record mean $μ_s$, standard deviation $σ_s$, and maximal value in the sample $X_s... | g14277 | [
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<p>I have 7 groups of data. I want to test if there is a significant difference between these groups of data.</p>
<p>However, some of this data is overlapping. ie. some data in Group 1 might be in group 3. Some data in group 6 might also be in group 7 for example. The groups are therefore not perfectly matched.</p>
<... | g58949 | [
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<p>I am currently implementing Latent Semantic Analysis in Java using the EJML library for the preliminary Singular Value Decomposition (SVD). I am testing my code against the original term frequency matrix provided in an oldish introductory paper by Landauer et al.:
<a href="http://lsa.colorado.edu/papers/dp1.LSAintro... | g58950 | [
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<p>Let $N(0,\Sigma)$ be a Gaussian distribution with mean $0$ and covariance $\Sigma$, a $p\times p$ matrix.</p>
<p>Is there an understanding the distribution $\mathcal{P}_{\mathbb{S}^{p-1}} (N(0,\Sigma))$? Is this equivalent to some well-studied distribution?</p>
<p>Note that Gaussians are not spherically symmetric ... | g445 | [
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<p>let $B(t)$ is brownian motion.<br>
Find $d(M(t))^2$,where $M(t)=e^{B(t)-\frac{t}{2}}$,</p> | g14279 | [
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<p>I conducted a mixed design ANOVA with two within-subjects factors: FactorA (2 levels), FactorB (2 levels), and one between-subjects factor: Group (2 levels). My main hypothesis regards the interaction FactorA*FactorB*Group.</p>
<p>This is the ANOVA table:</p>
<pre><code>Type III Repeated Measures MANOVA Tests: Pil... | g58951 | [
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<p>I am using log linear models (<code>loglm</code> function, library <code>MASS</code> of <code>R</code>) to evaluate if 3 variables in a 3 way contingency table are independent.</p>
<p>I build the model of mutual independence</p>
<pre><code>loglm(formula = ~A + B + C, data = test.t)
</code></pre>
<p>Which gives me... | g58952 | [
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<p><strong>Objective:</strong> Get the red line to go as high as possible.</p>
<p>I can control the values of the green and orange lines. There are like 50 other lines that I control and can pit against the red line as well.</p>
<p>What is a good way to determine which lines are correlated with movement in the red li... | g46899 | [
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<p>Can someone please explain the intuition behind mixed models in a nutshell? Whenever I read explanations, I get overwhelmed by notation and mathematical jargon. Can someone give me a simple example or motivation to help me understand the concept in a deeper way?</p> | g58953 | [
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<p>So I'm learning about deep learning. I first learned about stacked auto-encoders and now I'm learning about Restricted Boltzmann Machines. However non in the papers/tutorials I read I found them motivating why would one want to use RBM instead of auto-encoders. So what are the advantages of RBM over stacked auto-enc... | g58954 | [
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<p>My problem is the very idea of how to start the analysis of 2D point patterns, specifically how to find linear trends within their spatial pattern. </p>
<p>I have XY data points which are organized like in the plot, which I have manually marked with red lines in order to highlight what should be determined:</p>
<p... | g49542 | [
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<p>Suppose that you have a Poisson point process in $\mathbb{R}^d$ with rate (density) parameter $\rho$; I particularly care about $d=2$ if there is a solution in this special case. Given a finite realization, one can construct the minimal spanning tree of the ensemble. </p>
<p>I'd like to know (model/approximate) th... | g58955 | [
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<p>I've asked the <a href="http://math.stackexchange.com/questions/19180/detect-abnormal-points-in-point-cloud">same question</a> at Math SE, but the suggestion is that probably this question belongs here. </p>
<p>Given a list of <a href="http://en.wikipedia.org/wiki/Point_cloud" rel="nofollow">point cloud</a> in term... | g14283 | [
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<p>Suppose you construct a 95% confidence interval on a mean. Can you state that there is a 97.5% probability that the true population mean lies below the CI upper bound and that there is a 97.5% probability that the true population mean lies above the CI lower bound?</p> | g58956 | [
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<p>If there are two matrix of data, rows are all a person (under 50 users). In the first dataset, columns are attributes (over 500 columns) of a user with the rating 0 for does not exist, 1 for exist. Such as 1 for married, 0 for not. The second dataset is a choice of the user. 0 is no data, -1 is does not like, 1 ... | g21533 | [
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<p>I want to study the effect of the normality assumption on intervals like t-confidence interval and $\chi^2$ interval..</p>
<p>(1) Generate 1000 random samples from a normal population $N$($\mu$,$\sigma$). From
each of these samples, construct 95% confidence intervals for the population mean and for
the population v... | g58957 | [
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<p>So, I ran an ANOVA on a dataset which contains over 4500 data points. Without getting into too much detail, I was wondering if there is a simple explanation to this:
The p-value for my interaction term A*B is 0.145 => The interaction term is clearly insignificant. Both A and B are categorical variables with 2 levels... | g58958 | [
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... |
<p>I have implemented a simple Adaboost algorithm, using several weak classifiers, and when checking the values computed by it there are alphas with a negative value. Is that possible, or is there a bug in the implementation?</p>
<p>Thank you.</p> | g58959 | [
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<p>I'm wondering how an instrumental variable addresses selection bias in regression. </p>
<p>Here's the example I'm chewing on: In <em>Mostly Harmless Econometrics</em>, the authors discuss an IV regression relating to military service and earnings later in life. The question is, "Does serving in the military increas... | g58960 | [
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<p>I'm building a survival model for time to failure of widgets. Other members of the team want to convert the model to a cost flow model. The basic idea is that we can use the functional form of the survival function under the parametric approach (where we assume a logistic distribution) to estimate the cohort level s... | g14287 | [
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<p>Unbalanced panels are more common in economic fields, if I want to know the behaviour of firms, what will be the differences using unbalanced data panel. Are there advantages? Does it depend on analysis's period? Or it will be better use balanced panel?</p>
<p>Thanks!</p> | g14289 | [
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<p>Ok, forgive my ignorance, but I keep getting confused about something at the core of GLMs. Some textbooks describe the two main parts of a GLM as the link function and the distribution of the error terms. Others describe the two main parts as the link function and the variance function, where the variance function... | g58961 | [
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<p>I am working on some <strong>non-parametric bayesian based predictive analysis</strong> using <strong>R</strong>. I have a set of data which denotes various parameters of an online transaction. Based on these parameters I want to develop a model which will provide predictions for future online transactions.</p>
<p>... | g58962 | [
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<p>I've tried some recursive moving average formulae (to reuse a previous output instead of summing the whole <code>n</code>-long set for every <code>i</code>) I've managed to find but none of them produces the same results as a bare moving mean does. Is there a reliable recursive formula which would produce exactly (o... | g58963 | [
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<p>this is, I think, an easy question... I did a regression analysis in R, where I wanted to check the fit of my data to a specific formula I provided... I got this to work, I see the graph and the line showing the fit of the data, but I also would like to get actual regression value obtained from this calculation, how... | g8241 | [
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<p>I have generated a 95% confidence interval $(22,25)$ for a parameter using a nonparametric bootstrapping method. What I want to know is what value we use for the estimate of the parameter.</p>
<p>Is it the mean of all the bootstraps, the median of all the bootstraps, the original estimate before we bootstrapped fr... | g14295 | [
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<p>Are we still able to interpret the parameters in the same manner as we would in ordinary logistic regression? I'm asking this because I'm toying with the german credit data <a href="https://archive.ics.uci.edu/ml/datasets/Statlog+(German+Credit+Data)" rel="nofollow">https://archive.ics.uci.edu/ml/datasets/Statlog+(... | g14296 | [
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<p>I am not familiar with the concept of multivariate model and just learning about regression model. I am familiar with Autoregressive model and Moving Average.</p>
<p><a href="http://stats.stackexchange.com/questions/21665/multivariate-linear-regression-model">Multivariate regression model</a> provided cues to look ... | g58964 | [
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<p>I have a sample with some individuals, and also three variables measured for each individual, let's say $A$, $B$ and $C$.</p>
<p>There is a mild correlation between $A$ and $B$ and a mild correlation between $A$ and $C$</p>
<ul>
<li>$r_{AB} = 0.44$, and</li>
<li>$r_{AC} = 0.47$. </li>
</ul>
<p>I want to test if t... | g58965 | [
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0.0068929558619856834,
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0.005134406965225935,
-0.006663838867098093,
0.010233822278678417,
0.008092248812317848,
0.... |
<p>A common strategy in mass spectrometry of biological molecules is to upload observed spectra to a server so that they can be matched to a LARGE database of theoretical spectra of known molecules (a.k.a. <em>target</em> database). In order to control for false positives, a <em>decoy</em> database consisting of incorr... | g43382 | [
-0.003842543810606003,
-0.041806209832429886,
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0.00027426573797129095,
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0.03851921856403351,
0.016563111916184425,
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-0.003907174803316593,
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0.06473188102245331... |
<p>When dealing with data with factors R can be used to calculate the means for each group with the lm() function. This also gives the standard errors for the estimated means. But this standard error differs from what I get from a calculation by hand.</p>
<p>Here is an example (taken from here <a href="http://stats.s... | g58966 | [
-0.019008437171578407,
-0.08846696466207504,
-0.007397959008812904,
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0.015462399460375309,
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0.... |
<p>What would be the minimum sample size for a CART analysis? </p>
<p>I've found <a href="http://www.salford-systems.com/blog/dan-steinberg/item/11-rules-of-thumb-when-working-with-small-data-samples" rel="nofollow">this recommendation</a>:</p>
<blockquote>
<p>The original CART monograph discusses a study the autho... | g58967 | [
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0.04947580024600029,
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0.01388307474553585,
... |
<p>Do high VIF values for a a particular variable $x$ just indicate that it is highly correlated with at least one of the other variables in the model? Does it specify which variables and how many variables that $x$ is correlated with?</p> | g58968 | [
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<p>My research question is from education: To test whether groups (university, department, gender) differ based on their scores in a test, and whether there are any interaction effects, I'll do 3-way ANOVA? Data is unbalances (unequal cells).</p>
<p>My professor says I have to do SOS Type 1 (report parameter estimates... | g14302 | [
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0.030782582238316536,
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0.06... |
<p>If there is a species that is hyperabundant in a dataset and makes up 284/1638 individuals yet originated from just 1 of 10 traps. Is a quassi-poisson GLM sufficient providing residual deviance is under 1? or does this species need to be relativized or otherwise before proceeding to model selection? I really dont kn... | g58969 | [
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<p>Probably my question is a bit stupid, but I'm having some problems in writing down in R the out-of-sample forecasting with a Random Walk. I have a multivariate time series (y) and I want to estimate the out of sample forecasting (y(t+k)-y^(t+k/t) result with a RW, for k =1,6,12.
I write down this code, it works, but... | g43391 | [
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<p>This is a brief question because my lecturer mentioned it today in class but I don't quite understand. Why is omitted variable bias not a major problem in time series analysis?</p> | g58970 | [
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<p>Here are three regression equations:</p>
<p>$$
\begin{align}
Y &= \beta_1Z_{\text{math}}\qquad (1)\\
Y &= \beta_2Z_{\text{math}} + \beta_3Z_{\text{science}}\qquad (2)\\
Y &= \beta_4Z_{\text{department}} + \beta_5Z_{\text{math}} + \beta_6Z_{\text{science}} + \beta_7Z_{\text{university}} + \b... | g37473 | [
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0.0030... |
<p>Model:
$y_{it} = \alpha_{i}+\beta_1 D_{it} + \beta_2 G_i + \beta_3 (G_{i}\times D_{it}) + \epsilon$</p>
<p>G is a group dummy</p>
<p>D is a treatment</p>
<p>y is an outcome</p>
<p>data is a panel</p>
<p>$\alpha$ is a fixed effect</p>
<p>My question: if the only regressor in the model that is shared between th... | g14172 | [
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<p>I am trying to fit a three parameter inverse gamma distribution to my data in either R or Python. I would like to do this using maximum likelihood estimation (MLE). </p>
<p>The pdf of the three parameter inverse gamma is given by:</p>
<p><img src="http://i.stack.imgur.com/nOrUa.jpg" alt="enter image description he... | g14304 | [
0.03716059774160385,
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<p>This is an extension of a question I had previously asked. If the answer is a simple text-book question then feel free to reference it.</p>
<p>The problem started out as a need to compare two experimental data sets, one demonstrating ideal conditions, and the other, demonstrating what happens when a specific event ... | g58971 | [
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<p>I have three questions:</p>
<ol>
<li><p>For data with different response categories (likert type or ordinal) what type of correlation should be calculated? I know for ordinal variables <strong>Spearman's rank correlation</strong> can be used. Am I right? </p></li>
<li><p>Do I need to order the categories and recode... | g58972 | [
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<p>I am learning about <a href="http://en.wikipedia.org/wiki/Self-organizing_map">SOM</a> and also about <a href="http://en.wikipedia.org/wiki/Hopfield_network">Hopfield</a> networks.
I yet don't understand why I would use <code>SOM</code> over <code>Hopfield</code> and vice versa.</p>
<p>What kind of problems I shoul... | g14305 | [
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<p>I am currently trying to partition a scale-free ("big") graph (around 20k vertices, 500k edges) into appropriate sub-graphs. Having derived the Laplacian of the graph, I tried running an approach based on the spectral gap and Fiedler-vector, however, not really unexpectedly, ended up with vertex valuations (i.e. com... | g14306 | [
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<p>My question is basically as follows: what is the distribution of the absolute value of the Skellam distribution. Thanks!</p> | g14307 | [
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<ol>
<li>ARMA model is a stochastic version of recursive relation. For
deterministic recursive relations, we solve them and need initial
conditions to fully get the solution. So I wonder what is an "initial
condition" for ARMA model like?</li>
<li>In <a href="http://books.google.com/books?id=VHB4OSAmwcUC&lpg=PP1&a... | g58973 | [
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0.0... |
<p>Do user ratings of products — games, films, books, restaurants, etc. — tend to follow any particular distributions? If so, what form do they commonly take? Are there public data sources that show these distributions (e.g. for Amazon books, Netflix movies, etc.)?</p> | g58974 | [
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<p>I've got three groups A,B,C. Each has a different number of records and I have calculated the mean for each group. Now I want to know if these means are equal or not? What statistical test should I be doing?</p>
<pre><code>Group No.ofrec Mean
A 100 10
B 200 5
C 300 20
</code>... | g14309 | [
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0.03478987142443657,
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0.001... |
<p>I understand that Zipf's Rank-size distribution would allow me to estimate the sales of a book given the amazon sales rank. How can I fit the distribution without knowing book sales leading to a rank. Sales Rank is calculated with time since last sale in mind, a decay function.</p> | g14310 | [
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<p>Suppose I have this MA(1) model: </p>
<p>$y_t = \mu + \epsilon_t + \theta \epsilon_{t-1}$ with $\epsilon_t \sim \mathcal{N}(0,\sigma^2)$ </p>
<p>The marginal distribution of $y_t$ for all $t$ is $\mathcal{N}(\mu,\sigma^2(1 + \theta^2))$ but the classical theory says that since the $y_t$ variables are not indepen... | g14313 | [
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<p>Say I am about to receive 5 cash prizes and I have the probability of receiving each cash prize. Let's denote a set of cash prizes with $k$. So, below is the set of cash prizes and the set of corresponding probabilities:
$$k=\{65,25,30,54,30\}$$
$$p(k)=\{0.8,0.5,0.25,0.2,0.4\}$$</p>
<p>Hence, the expected value of... | g58975 | [
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<p>Are there any examples of machine learning in our PC's? The only one that I know is Windows Speech Recognition application. </p>
<p>I do not mean any add-ons. I mean any basic applications that are available in most PC's.</p>
<p><strong>EDIT:</strong> Any reference would be helpful.</p> | g58976 | [
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<p>People got a list of different documents and were asked if they find things important or not and if they think the documents would be easy to get or not.
People belong to different groups and have different professions.
For answering they had three choices:<br>
0 = not important<br>
2 = moderately important<br>
4 = ... | g58977 | [
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0.02714558131992817,
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0.005551437847316265,
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... |
<p>We just had a courses on panel data in econometrics, and longitudinal data in classic statistics,</p>
<p>And I was wondering if something similar exists in engineering, for example:</p>
<p>You have 50 identical cars and you ride with them until a particular component fails. You use the data of the car (forces on t... | g58978 | [
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<p>I have obtained the following results in R from a random coefficient Poisson analysis.</p>
<p>Generalized linear mixed model fit by maximum likelihood ['glmerMod']
Family: poisson ( log )
Formula: frequency ~ 1 + insgen + ageveh + make + area + (1 | ID)
Data: Panel </p>
<pre><code> AIC BIC logLik d... | g14317 | [
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<p>On which data should the lift be calculated i.e. Training set or Test set and why?
What does the lift value 115% mean </p> | g14319 | [
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<p>I'm currently attempting to forecast visitor data for stores. My dataset includes daily visitor totals of three years. Note that the dataset isn't complete (stores can be closed for a few days, etc). I've augmented the dataset with weather data per day and holiday information (I have about 18 features per datapoint,... | g58979 | [
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<p>Say we have observations $x_1 \dots x_n$ and we have some sort of Bayesian framework where we would like to estimate a distribution for the mean $\mu$ of our observations and the variance $\sigma^2$ of our observations (these distributions will then be updated based on further observations). I have 2 questions:</p>
... | g9239 | [
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... |
<p>This is a long post so I hope you can bear with me, and please correct me where I'm wrong.</p>
<p><em>My goal is to produce a daily forecast based on 3 or 4 weeks of historical data.</em> </p>
<p>The data is 15 minute data of the local load of one of a transformer lines. Im having trouble finding the model order o... | g58980 | [
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<p>A course problem given by some unknown in a discussion forum is the following:</p>
<p>A student has been given data of age at death of novels (67 data points), age at death of poems (32 data points) and age at death of nonfiction (24 data points). Then lecturer asked to use graphical and numerical methods to descri... | g58981 | [
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0.07260710000991821,
0.06718729436397552,
-0.018796280026435852,
-0.028331127017736435,
-0.024434825405478477,
0.07808665931224823,
-0.007307746447622776,
0.07444026321172714,
0.... |
<p>I am using an automatic model selection procedure, "step". The model of depart (the biggest possible) is a polynom, say of the 4th degree.</p>
<pre><code>Depart<-lm(y~x+I(x^2)+I(x^3)+I(x^4))
Final<-step(Depart)
</code></pre>
<p>I need to transform the Final model to a corresponding function. How can i do th... | g58982 | [
-0.005889246705919504,
-0.022314904257655144,
0.00229042605496943,
-0.07709362357854843,
0.0043366593308746815,
-0.04342092201113701,
0.021527700126171112,
0.04507310315966606,
-0.01033842284232378,
0.018633320927619934,
-0.12247712910175323,
0.024636702612042427,
0.043808069080114365,
-0.... |
<p>I have a function <code>IR</code> that depends on several (maybe 100) <code>input random variables</code>.
I know <code>IR varies between 0 and 1</code>. Therefore it has two discontinuities, one at <code>IR=0</code> and the other at <code>IR=1</code>.</p>
<p>I also know that the <code>pdf of IR</code> takes non-z... | g14329 | [
-0.02088080532848835,
-0.0548844188451767,
-0.0021039536222815514,
0.03587434068322182,
0.014237449504435062,
0.0038395633455365896,
0.017446201294660568,
0.07149675488471985,
-0.05902635678648949,
-0.017857292667031288,
-0.02941565029323101,
0.010506698861718178,
0.01688467711210251,
0.02... |
<p>The data I am using are sales person data. The data contain six independent variables (six vulnerabilities) scored 1-20 and the output is win/loss of the deal. My question is how do we know which variable or combination of variables are affecting the output i.e. win/loss, and what should be the methods or step to co... | g58983 | [
-0.00470284977927804,
-0.043178219348192215,
-0.024669986218214035,
0.03047986328601837,
-0.008176922798156738,
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0.01842368021607399,
-0.044130224734544754,
-0.006183272693306208,
-0.04117407649755478,
0.01135918591171503,
0.05658182129263878,
0.020253345370292664,
0.0... |
<p>I'm new to statistics and have to do some research analysis using SPSS. I need to know, what is the purpose of removing outliers? I want to normalize my set of data obtained through a national survey, but there are a few variables that do not show a bell curve even if I have transformed my data. log, ln, sqrt etc. I... | g58984 | [
0.016128459945321083,
-0.002724897116422653,
0.01901412568986416,
-0.045792095363140106,
-0.027013178914785385,
0.010638314299285412,
0.012269651517271996,
0.04087800905108452,
-0.000778986606746912,
-0.07518556714057922,
-0.0032500973902642727,
0.03714165464043617,
-0.010880502872169018,
... |
<p>Assume we have a linear model <code>Model1</code> and <code>vcov(Model1)</code> gives the following matrix:</p>
<pre><code> (Intercept) latitude sea.distance altitude
(Intercept) 28.898100 -23.6439000 -34.1523000 0.50790600
latitude -23.643900 19.7032500 28.4602500 -0.42471450
sea.dis... | g14333 | [
-0.011436184868216515,
-0.046719636768102646,
-0.027435295283794403,
-0.013260545209050179,
0.02353268675506115,
-0.00394200487062335,
0.04301762953400612,
-0.009427492506802082,
-0.016930699348449707,
-0.0029178864788264036,
-0.016455961391329765,
0.07715131342411041,
0.015159751288592815,
... |
<p>My question is related to <a href="http://academia.stackexchange.com/questions/23556/should-i-repeat-experiment-affected-by-external-factors-until-achieving-consiste">this one</a>. I'm working on an experiment involving transferring data between different locations all over the world via the Internet. As the Interne... | g14334 | [
-0.019170748069882393,
-0.012077155523002148,
0.0031698013190180063,
-0.021721385419368744,
-0.006343527231365442,
-0.054538242518901825,
0.023930154740810394,
-0.03781907632946968,
-0.09366704523563385,
0.03793805092573166,
0.006815230939537287,
0.005646341014653444,
-0.03590112924575806,
... |
<p>Was wondering if anybody could explain how I can calculate the answer. Would be much appreciated.</p> | g14336 | [
0.026436349377036095,
0.060913652181625366,
0.0270462017506361,
-0.004559368826448917,
0.03017117641866207,
-0.026896491646766663,
0.004566843155771494,
0.07008802145719528,
-0.03857431933283806,
-0.02267381176352501,
-0.07920843362808228,
0.06646502763032913,
0.00849910918623209,
-0.01675... |
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