question stringlengths 37 38.8k | group_id stringlengths 2 6 | sentence_embeddings listlengths 768 768 |
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<p>Suppose I have a multivariate, compositional dataset that depicts the concentration of different elements. However, the data are not available on a single scale; i.e., some are of form 0.00x while others are integers. Should I apply any kind of normalization / standardization technique before applying, or do I need ... | g61063 | [
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<p>I have a question regarding the <code>ppois</code> function in R:</p>
<ul>
<li><code>ppois(x,lambda,lower.tail=TRUE)</code> gives $P[X>x]$</li>
<li><code>ppois(x,lambda,lower.tail=FALSE)</code> gives $P[X\le x]$</li>
</ul>
<p>How can I calculate $P[X=n]$? I mean is there any function in R for this?</p> | g61064 | [
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<p>I have a trained logistic regression model that I am applying to a testing data set. The dependent variable is binary (boolean). For each sample in the testing data set, I apply the logistic regression model to generates a % probability that the dependent variable will be true. Then I record whether the acutal value... | g61065 | [
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<p>I have a situation, where I need to classify items into groups (lets say 6). When I ran k-means 90% of my data fall in 1 group remaining 10% fall in other groups. What's next step?
In order to further group the data, I have taken the 90% data group and once again I ran k-means.This time I have 15 new groups within t... | g61066 | [
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<p>For every year, for eight years, I have a set of projects (n=332). The number of projects that exist in each year varies (for example, some years there are 10 projects others there are 60). In each year, projects are either approved or not approved based on a score. I want to compare the means for approved and no... | g17492 | [
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<p>Consider the multivariate regression with random predictors as described in Izenman's <em>Modern Multivariate Statistical Techniques</em>, that is, </p>
<p>$X : r \times 1$ and $Y: s \times 1$ are jointly normally distributed with respective mean vectors $\mu_X$ and $\mu_Y$ and they have joint covariance matrix $$\... | g537 | [
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<p>I usually use text mining, graph mining, Information retrieval, and natural lanuage processing. Also i will use the fundamental concepts of data mining like classification, association and clustering. Please suggest me solution and study material( text books).</p> | g49612 | [
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<p>I am new to time series analysis; I am not even sure if this is even a TS problem. I have looked at other TS posts, but I have a hard time to translate the responses to my needs. For now I am hoping for help to define the procedure on how to solve my problem.
For the future I hope to be able to "fish" by myself. Th... | g17494 | [
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<p><a href="https://en.wikipedia.org/wiki/McNemar%27s_test" rel="nofollow">McNemar's test</a> is a special example of the <a href="https://en.wikipedia.org/wiki/Sign_test" rel="nofollow">binomial sign test</a>, but the ('vanilla') sign test suffers from bias due to ignoring differences equal to zero.</p>
<p>McNemar's ... | g61067 | [
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<p>Does anyone know any metric that measure <strong><em>topic centrality</em></strong> or topic stickiness (I've seen someone used this term too). For example </p>
<p><em>Cluster 1</em></p>
<p>$d_1$ = { a, b, c },
$d_2$ = { b, c, d }</p>
<p>and
<em>Cluster 2</em></p>
<p>$d_3$ = { a, b, c },
$d_4$ = { d, e, f }</p>... | g9748 | [
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<p>I'm playing around with logistic regression (using scikit-learn, which uses liblinear)</p>
<p>I created some example data sets, and it often works well. Since I created the data sets, I already know the optimal bounds, and a 100% correct linear classifier is possible.</p>
<p>Fairly often (~1 in 10) the predicted b... | g61068 | [
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<p>I am new to multilevel models and I am basically wondering whether I can use a multilevel model at all, given the structure of my data.</p>
<p>I have collected data on membership of lobby groups in committees used by the Directorates-General (DGs) of the European Commission (the DGs are a bit like ministries in a n... | g61069 | [
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<p>I read a fascinating free <a href="http://www.plosmedicine.org/article/info%3adoi/10.1371/journal.pmed.0020124" rel="nofollow">article</a> about why most published research findings might be false. I am able to follow along almost completely, except for one tiny part.</p>
<p>In it, the author, Ioannidis, writes</p>... | g61070 | [
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<p>I'd like to evaluate the performance of an algorithm which learns to approximate a discrete PDF for a latent variable given some noisy input.
Now, is there a standard test to evaluate the goodness of that approximation?
I would like to train the algorithm with synthetic data and then see how close the approximation ... | g17495 | [
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<p>Debugging MCMC programs is notoriously difficult. The difficulty arises because of several issues some of which are:</p>
<p>(a) Cyclic nature of the algorithm</p>
<p>We iteratively draw parameters conditional on all other parameters. Thus, if a implementation is not working properly it is difficult to isolate the ... | g61071 | [
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<p>As you know, there are two popular types of cross-validation, K-fold and random subsampling (as described in <a href="http://en.wikipedia.org/wiki/Cross-validation_%28statistics%29">Wikipedia</a>). Nevertheless, I know that some researchers are making and publishing papers where something that is described as a K-fo... | g61072 | [
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<p>I am comparing three relatively simple GLMs having a Gamma distribution with AIC and BIC. The aim is to identify the effects of fertilizers (fdung), year and site on biomass of a specific grass species. Hence, the aim is not to predict new values but merely to identify the effects of the three factors.</p>
<p>Here ... | g34150 | [
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<p>There is a similar question in <a href="http://stats.stackexchange.com/questions/74833/exk-under-a-gaussian?noredirect=1#comment145996_74833">$E(x^k)$ under a Gaussian</a>. However, it doesn't seem to be trivial when $\mu\ne0$. As mentioned in the previous question <strong>$k$ is not an integer</strong>.</p>
<p>The... | g61073 | [
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<p>I'm trying to understand the process for statistical testing for principal component analysis or partial least squares.</p>
<p><strong>Step 1. PCA:</strong>
I feel that I have a not-terrible understanding of PCA: You find the ellipsoid described by the covariance matrix of the data, and then successively take the l... | g61074 | [
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<p>There are many situations where you may train several different classifiers, or use several different feature extraction methods. In the literature authors often give the mean classification error over a set of random splits of the data (i.e. after a doubly nested cross-validation), and sometimes give variances on t... | g47194 | [
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<p>I might be missing something basic - but it appears that the strong law of large numbers covers the weak law. If that case, why is the weak law needed?</p>
<p>Thanks!<br>
Liran</p> | g48239 | [
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<p>I have time series data that can be fitted by a constrained non-linear function (non-linear in the parameters to be estimated). I'd like to use the method of Lagrange Multipliers (<a href="http://en.wikipedia.org/wiki/Lagrange_multiplier" rel="nofollow">link</a>), specifically R's <code>Rsolnp</code> package (<a hr... | g17502 | [
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<p>I´m trying to find variables predicting a disease by using first logistic regression for each variable on the disease and then entering the significant variables into a multiple logistic regression model. However, one of the variables in the multivariate model is a clinical score, which contains some of the variable... | g61075 | [
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<p>How do I do regression with many replicates on the dependent variable at each level of the independent variable?</p>
<p>Pardon my ignorance on this as its my first time posting here.<br>
I'll try to be as precise as can be.<br>
I have data that looks as follows: </p>
<pre><code> X, y1, y2, y3, ... | g47200 | [
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<p>I have data from questionnaire from school. 35 questions are various questions (influence of friends etc.)</p>
<p>Possible answers for 35 questions are "definitely yes", "mostly yes", "mostly no" and "definitely no".</p>
<p>I did hierarchical clustering using <code>hclust</code> in R. Then I used <code>cutree</cod... | g61076 | [
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<p>I have about 900 flies that either like sugar or are neutral (about 50% in each group). However, on closer inspection I do notice a trend that sugar liking flies are from bins 1-10 (each bin has about 45 flies), while the neutral ones tend to be from 11-20 bins. I'm not sure why, but is there a statistical test I ca... | g61077 | [
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<p>R is creating dummy variables for the color variable (color is either white or red) in my linear regression model. For example, color:pH returns the interaction term colorred:pH. Some questions: </p>
<p>Why is R only returning <code>colorwhite</code> for some interaction terms and <code>colorred</code> with other t... | g61078 | [
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<p>I'm working with a microarray data set where the batches are completely confounded treatment time, i.e. time t1 is all in batches b1 and b2, and time t2 is all in batches b3, b4, and b5. I know this means that I can't do much abound looking for differential expression over time.</p>
<p>However, we do have the orig... | g27575 | [
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<p>I have a large data set (>1000 obs) and i'm performing regressions tests, both linear and logistic, on a series of clinical outcomes.</p>
<p>In this test I verify the effect of interactions between two cat variables by creating a dummy interaction variable with the two vars joined in one (with R is done using the i... | g363 | [
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<p>i'm developing a hidden semi-Markov model left-right . In a left-right model a sequence of $M$ states starts in state 1 and ends in state M, with no repetition of states. Since the model is semi-Markovian a self transition $a_{ii}=0$ is not allowed. I think the last row of the matrix should be 0, but the rule is $\s... | g11224 | [
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<p>I've conducted a multiple linear regression with 3 predictors, A, B, and C, all three on the same scale.</p>
<p>One of the three predictors displays a smaller range than the other two (range A=0.53; B=0.98; C=0.86), as well as a smaller standard deviation (SD A=0.18; B=0.30; C=0.25).This is precisely the predictor ... | g61079 | [
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-0.03422534093260765,
-0.023156700655817986,
0.02233182266354561,
0.0033935909159481525,
0.06589344143867493,
0.02... |
<p>I have only a small dataset. I want to 1. select the most predictive features out of a large candidate pool and 2. get an estimate of their expected predictive performance.</p>
<p>In <a href="http://books.google.at/books?id=tVIjmNS3Ob8C&pg=PA245&lpg=PA245&dq=elements%20statistical%20learning%20cross-va... | g61080 | [
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0.043... |
<p>I have a data set containing three groups (A, B, C). Group A and Group B have undergone two different types of training designed to improve the same thing. Group C is my control group with no training. I have specific hypotheses stating that:</p>
<p><p>Group A will be better than group C
<p>Group B will be bett... | g61081 | [
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<p>I have various samples on which three survival time variates have been collected. How can I compare the difference of such variates taking into account within subject correlation (possibly in R)?</p> | g17510 | [
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<p>I'm currently reviewing an article where authors presented distribution statistics that look erroneous to me. But I'm not able to find a way to ascertain it. The article presented results with a mean of 95% and standard deviation of 25%. Maximum value can't be more than 100% and minimum value can't be less than 0%. ... | g61082 | [
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<p>I'm trying to write a bit if R code to run the estimator in
"Estimating Vector Autoregressions with Panel Data" Econometrica 56-6 (1988). </p>
<p>I'm stuck on equation (3.12) I feel like $Z_{ir}$ and $Z_{is}$ should be of different lengths, and therefore the dot product $Z'_{ir}Z_{is}$ isn't a valid operation. If ... | g61083 | [
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<p>I am working on decision tree model and a value in dependent variable (churn) is very less.
we have 1.5 lac records and only 1700 records have churn = 1.
While using decision tree model, tree is not created, quality of model is okay but it is not able to predict where churn should be 1.</p>
<p>Please let us know if... | g34152 | [
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<p>I'm taking an intro to marketing class this semester and the course requires us to buy a software which looks nothing more than a bunch of excel macros. From the <a href="http://www.decisionpro.biz/products/marketing-engineering-for-excel">software's page</a></p>
<blockquote>
<p>Marketing Engineering for Excel pr... | g61084 | [
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<p>I am using a particle filter to estimate the parameters($\Phi_{n\times1}$) of a non-linear model. Say my input (observations) is $t=1:k$, I will have a vector of length $k$ for each of the parameter estimates. Thus, at the end of the particle filter, I will end up with a parameter estimate matrix ($\Theta$) of $k\ti... | g47213 | [
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<p>In a LASSO regression scenario where</p>
<p>$y= X \beta + \epsilon$,</p>
<p>and the LASSO estimates are given by the following optimization problem</p>
<p>$ \min_\beta ||y - X \beta|| + \tau||\beta||_1$</p>
<p>Are there any distributional assumptions regarding the $\epsilon$? </p>
<p>In an OLS scenario, one wou... | g37981 | [
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<p>If I'm using OLS linear regression, and I want to know the uncertainty of my forecasts I can quantify it using residuals (MSE, median absolute deviation, etc). But if I'm using robust linear regression that down-weighs some observations as outliers and I don't have access to those weights, how can I accurately quant... | g47214 | [
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<p>I have the following data:</p>
<p>IV = 2 levels (Experimental Group + Control Group).</p>
<p>DV = I'm using signal detection variables i.e. (Hits, CRs, FAs & Misses) </p>
<p>Both groups were tested twice so therefore I have 2 sets of DVs for each group (i.e. Hits 1 & 2, CRs 1 & 2) and so on.</p>
<p>I... | g61085 | [
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<p>Does anyone know if the following has been described and (either way) if it sounds like a plausible method for learning a predictive model with a very unbalanced target variable?</p>
<p>Often in CRM applications of data mining, we will seek a model where the positive event (success) is very rare relative to the maj... | g61086 | [
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<p>I'm not sure if I'm asking something stupid or off topic here, but I can't think where can I ask this question.</p>
<p>suppose I am going to do a univariate logistic regression on several independent variables, like this:</p>
<pre><code>mod.a <- glm(x ~ a, data=z, family=binominal("logistic"))
mod.b <- glm(x... | g17515 | [
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<p>I am trying to process a set of tweets, by using its length to determine the probability of spam. </p>
<p>The data looks like this, given 2000 tweets, n is the tweet length (number of words)</p>
<pre><code>when n = 1, relevant tweets = 0
when n = 2, relevant tweets = 10
when n = 3, relevant tweets = 20
when n = 4,... | g17517 | [
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0.015925979241728783,
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0.026... |
<p>I have two linear regressions. The linear coefficients of both of them are very close to $1$. The first plot seems reasonable linear regression, while the second one is tricky since if the bottom left part or the top right part of the data (they are quite random) are fitted, we can not get a close-to-1 coefficient.<... | g17518 | [
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<p>In a survey done to find the characteristics consumers prefer while choosing a retail store. Respondents were given 9 options and to scale them from 1-10 one for the most preferred value. Now we have responses in which respondents have given same ratings to multiple characters. Example given:</p>
<pre><code>pric... | g61087 | [
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<p>I am from an economics background and usually in the discipline the summary statistics of the variables are reported in a table. However, I wish to plot them. I could modify a box plot to allow it to display the mean,sd and min and maximum but I don't wish to do so as box plots are traditionally used to display medi... | g61088 | [
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<p>Assume that you need to build a linear model to make predictions for new observations, and that there is uncertainty about which subset of variables should be included in the model. You are only interested in making predictions, there is no theory available to guide variable selection, and you aren't interested in d... | g61089 | [
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<p>I'm using a Poisson binomial distribution for co-occurrence testing.</p>
<p>I've 2 variables: $X \sim Bin(p_x,n)$ and $Y \sim Bin(p_y,n)$, where $p_x$ and $p_y$ are the probabilities, and both variables have the same number of data $n$.</p>
<p>Then, let $Z_{\rm th} = X+Y \sim PoisBin(p_x,p_y,n)$.
From this theoret... | g61090 | [
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<p>Let $\varepsilon$ be a Gaussian distributed random variable with mean $\mu_0$ and standard deviation $\sigma_0$. Is it possible to compute/approximate the expected value</p>
<p>$$
\begin{eqnarray}
& &\mathbb{E}\left[\Phi\left(\frac{\varepsilon-\mu_1}{\sigma_1}\right)\mid\varepsilon<c\right]=...\\
& &... | g61091 | [
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<p>Every parametric test has the assumption that the sample means are following a normal distribution. This is the case if the sample itself is normal distributed or if approximately if the sample size is big enough. but why do they have that assumption? I thought the test statistic is used to make a decision and they ... | g61092 | [
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<p>I am trying to pick up and learn some statistics. I am not good at it, so please forgive me if I'm asking something naive.</p>
<p>Suppose you have a set of data values, say 10k of them, and the format looks like: 1.256, 9.264, 4.483, 460.357....</p>
<p>How to identify the distribution of it?</p>
<p>Thank you very... | g61093 | [
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<p>An event occurs with a mean of 15 times per hour and a standard deviation of 10 times/h.
From the population a sample of 100 individuals is drawn. What is the probability that the sample mean will be between 14 and 16?</p>
<p>I want to solve this problem assuming that the event follows a Poisson distribution (I can... | g22089 | [
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<p>I have a large set of data comprising triples of points (t, y1, y2). At each t, I have a distribution of y1 and y2 points, each of which is approximately normal.</p>
<p>I would like to create a plot of y1 versus y2 (mean values) and add a 90% or 95% confidence interval envelope.</p>
<p>I would appreciate any advic... | g61094 | [
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<p>I have a data set of 30 million consumers of an electric utility service.
- consumption
- billing
- smart meter readings sampled every 5 seconds
- market share data area wise</p>
<p>Any suggestions on how to compute weights for underlying factors that can predict customer satisfaction?</p>
<p>This is an initial pl... | g61095 | [
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<p>Before asking, I read similar questions, but none of them lead to satisfying answers for my specific interest.</p>
<p>I want to homogenize a climate time series of precipitation of the Dominican Republic over 64 years (1940-2003). For that, it is really important to select a reference series among a group of candid... | g61096 | [
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<p>What are some additional ways to write the null and alternative hypotheses below (i.e., mathematically equivalent)?</p>
<p>Null hypothesis: H0: µ1 = µ2 the two population means are equal</p>
<p>Alternative hypothesis: H1: µ1 ≠ µ2 the two population means are not equal</p>
<p>OR </p>
<p>Null hypothesis: H0:... | g61097 | [
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... |
<p>Given</p>
<p>$$f_{(U_1,U_2)}(u_1,u_2)=\begin{cases} 1/2& -u_1<u_2<u_1 \text{ and } u_1 - 2 < u_2 < 2 - u_1 \text{ and } 0 < u_1 <2\\ 0& \text{otherwise}\end{cases}$$</p>
<p>I found that $$f_{(U_1)}(u_1) = \begin{cases} u_1 & 0<u_1<1\\2-u_1 &1<u_1<2 \\0 & \text{othe... | g17522 | [
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... |
<p>I have a bivariate data set where x and y values, both continuous variables, correlate well (visually speaking) when x and y are small. As the values of x and y increase, the correlation decreases to an eventual random state when x and y are large. My question is, given a y value, I would like to know the probabilit... | g61098 | [
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... |
<p>I have two independent populations (up and down), each population contains three categories 1,0,-1.</p>
<p>For example:</p>
<pre><code> up = 1,1,1,1,0,0,1,1,-1,-1,1
down = 1,-1,1,-1,0,1,-1
</code></pre>
<p>These populations are not the same size as each other and are much larger than the example above (a... | g17523 | [
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0.03752482682466507,
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0.03867809474468231,
0.021523941308259964,
... |
<p>I have a design with four factors
Frame (positive negative neutral)
Graphic ( graph no graph)
Color (red grey) nested in graphic
Position of color (nested in color, which is nested in graphic)</p>
<p>I am having difficulty understanding if this is an incomplete nested design or a split plot design. </p>
<p>... | g17524 | [
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0.00017212242528330535,
-0.03... |
<p>Is there any convention regarding the minimum information that should be included in a table showing a linear regression output? </p>
<p>The reason for this question is that I want to make the output as easy to understand as possible. I have graphed the main findings but I want to include the other outputs in a det... | g47235 | [
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0.05940974876284599,
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0.05091402307152748,
0... |
<p>I have 2 vectors of raw values. I need to do a percentile rank correlation and an ordinal rank correlation between them in Matlab. </p>
<pre><code>Vec1 = [25 28 29 29 31 32 33 33 33 35 37] ;
</code></pre>
<p>I'm using <code>corr</code> function in Matlab with <code>type=Spearman</co... | g47237 | [
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<p>Suppose $p({\bf x},\theta), \theta \in {\bf \Theta} \subset {\bf \mathbb R^k}$ is a (regular) family of distributions.</p>
<p>The score function is defined as $s({\bf x},\theta)=\frac{\partial}{\partial \theta}log(p({\bf x},\theta))=grad(p({\bf x},\theta))$, the Fisher information matrix as ${\bf I}(\theta)=var({\b... | g61099 | [
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<p>I have pupils clustered within schools, with a binary outcome (pupil experiences bullying or does not). So far all predictors are pupil-level data, and I run a the same model (same predictors) on each year of data. My teacher was talking about adding a school-level predictor: the size of the school, which will simpl... | g571 | [
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<p>I have a data set consisting of reaction time (RT) measurements. These will be used to calculate the duration of experimental trials in an MRI study. In each block (experimental condition) there are 10 trials. Now, due to various issues, there are some missing RTs. Due to the nature of MRI analysis, I need value... | g27752 | [
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<p>I am trying to model some data using glmnet package in R.
Let say I have the following data </p>
<pre><code>training_x <- data.frame(variable1=c(1,2,3,2,3),variable2=c(1,2,3,4,5))
y <- c(1,2,3,4,5)
</code></pre>
<p>(this is a simplification; my data is much more complicated). Then I used the following code ... | g27753 | [
0.02574542537331581,
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<p>I trained a model with</p>
<pre><code>java -Xmx6g -cp /usr/share/java/weka.jar weka.classifiers.bayes.NaiveBayes -t train.arff -d foo.nb
</code></pre>
<p>and I want to score a test file with it.</p>
<p>I tried</p>
<pre><code>java -Xmx6g -cp /usr/share/java/weka.jar weka.classifiers.bayes.NaiveBayes -T test.arff ... | g17533 | [
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0.0263509601354599,
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-0.07732418179512024,
0.0005482054548338056,
0.012018052861094475,
0.044902872294187546,
0.... |
<p>I have data on 26 participants (13 from computing and remaining 13 from non computing) who have participated in my research. Each participant is treated with a lab module (Hands on Robotics Session). Now each participant will be evaluated using a rubric on scale of 1 to 4. This experiment has both pre and post test.... | g61100 | [
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0.03456379100680351,
0.026042962446808815,
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-... |
<p>Alright, I expect this is a silly question, but I don't actually know, so.</p>
<p>Suppose there is some random variable that's distributed on the reals, and all I know about the distribution is its mean $\mu$ and its variance $\sigma^2$. Maximum Entropy would have me say that I should choose the Normal distribution... | g17534 | [
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<p>I've frequently read that knowledge of Perl or Python complements SAS or R, and seen that Perl is a desirable language in job advertisements. </p>
<p>Can anyone clarify this a bit more? Is Perl limited to text mining & database updates or does it have other applications in the statistics world? Thanks!</p> | g61101 | [
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<p>We want to determine the public opinion about a recently administered intervention in a health care network. There's a brief questionnaire of 10 Y/N questions in which we'd like to estimate proportions within a specific margin of error (+/- 3%). Based on historical data, we feel we can reliably estimate response pro... | g61102 | [
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0... |
<p>This question comes from trying to analyze my recent exam (exam I have given and corrected) statistically. I have a list of questions (20 in total) and each question is given a score from 0 to five, so total possible score is 100. Then I define pass/not pass via some cutoff
(I give notes on the A-B-C-D-E-F scale, b... | g61103 | [
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0.0286... |
<p>I submitted the final in a theoretical stats class and had trouble with several problems, but part of one is bugging me because it seems like it should be simple. Lets say we have two random independent variables $X$ and $Y$, each with their respective pdf $f(x)$ and $f(y)$. The support for each is:
$-\infty < ... | g17536 | [
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0... |
<p>I am trying to use the subset argument to restrict which observations are plotted. The doc for xyplot says the subset argument should be</p>
<p>"An expression that evaluates to a logical or integer indexing vector."</p>
<p>Here are two examples trying both, but I can not get either to work.</p>
<pre><code># Gener... | g17537 | [
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0.005631151609122753,
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-0.02938220277428627,
0.08071426302194595,
0.06141791120171547,
-0.014964044094085693,
0.00... |
<p>I have trouble understanding the delineation of "non-parametric" methods. It seems to me most non-parametric methods are parametric, just on a different space than the "standard ones". </p>
<p>Graph-based inferences are often described as non-parametric, but graphs are fully described by the set of adjacency matrix... | g61104 | [
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0.055182211101055145,
0.0178... |
<p>I've heard a bit about using <a href="http://stats.stackexchange.com/questions/9842/getting-started-with-neural-networks-for-forecasting">neural networks to forecast time series</a>, specifically <a href="http://stats.stackexchange.com/questions/8000/proper-way-of-using-recurrent-neural-network-for-time-series-analy... | g61105 | [
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0.... |
<p>I am just trying to understand what the relationship is between a normal multiple/simple regression vs. multiple/simple regression when the variables are differenced.</p>
<p>For example, I am analyzing the relationship between deposit balance ($Y_T$) vs. market rates ($R_T$)
If I run a simple linear regression, the... | g17542 | [
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0.009682372212409973,
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-0.0... |
<p>I'm modeling some periodic data with a second-order autoregressive model, as follows:</p>
<p>$$
x_3 = a_{1}x_1 + a_{2}x_2
$$
$$
x_4 = a_{1}x_2 + a_{2}x_3
$$
$$
...
$$
$$
x_n = a_{1}x_{n-2} + a_{2}x_{n-1}
$$</p>
<p>I'm modeling the raw data here (imagine $x_i$ as a scalar pixel value, say, for $n$ time poin... | g41451 | [
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0.... |
<p>Logistic, linear and probit regression can be written in terms of Generalized Linear Model (GLM). Can the multinomial logit regression be written in terms of GLM as well?</p> | g48544 | [
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... |
<p>I'd like to combine several variables into one variable. Here is some context:</p>
<p>Let's say I have two variables <code>Red.Beads</code> and <code>Blue.Beads</code> and each observation of each variable is a number representing the number of beads for that observation. Say each red bead has a mass of 5 grams, ... | g61106 | [
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... |
<p>I've constructed a database based on chart review of patients. Patients had a variety of tests performed (37 different types, which were either positive, negative, or not performed aka 1/0/blank - I presume this is consistent with a dichotomous/nominal variable). A total of 31 possible diagnoses could have resulted,... | g61107 | [
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<p>Maxwell and Delaney (1990) wrote that the multivariate approach should not be used for a repeated measures ANOVA for within subjects effects if n is less than "a + 10" (a is the number of levels for repeated measures). My data has 7 time levels and 2 levels for location and 2 levels for condition (control vs. non-c... | g61108 | [
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... |
<p>At work we have a hardware device that is failing for some yet to be determined reason. I have been tasked to see if I can make this device <em>not</em> fail by making changes to its software driver. I have constructed a software test bench which iterates over the driver functions which I feel are most likely to cau... | g17550 | [
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<p>I am trying to understand how I can use resampling techniques to compliment my pre-planned analyses. This is not homework. I have a 5 sided die. 30 subjects call a number (1-5) and then roll the die. If it matches it's a hit, if not it's a miss. Each subject does this 25 times. </p>
<p>N is the the number of trials... | g38111 | [
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0.007407084107398987,
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... |
<p>Well my objective is to predict solar energy radiation at a particular location given some features like wind, temperature, humidity ...</p>
<p>I have a total data for 10 years where I have the measurement for the features at 100 locations(nearby) and the solar energy measurement at the target location for each day... | g61109 | [
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0.020... |
<p>I'm looking for visualization ideas for the following data:</p>
<blockquote>
<ul>
<li><p>I have a $10\times 12$ grid of points $(x_i,m_j)$, where the $x_i$ are a set of distances (e.g. 1,2,..., 10 m) and the $m_j$ are the 12 months. </p></li>
<li><p>At each $(x_i,m_j)$, I have 4 values $q_1,\ldots,q_4$ which ... | g61110 | [
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0.08612753450870514,
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0.04631197452545166,
0.09531354904174805,
0.01... |
<p>I am new to the area of statistics and I am hoping you can suggest methods I may use. Sorry if this is long but I might as well be as clear as possible on my first post :)<br>
<em>What I am worried most is that I may miss out on assumptions and draw conclusions based on statistical tests that, in fact, cannot be app... | g27822 | [
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0.... |
<p>Hi there I have a very important question for my statistical analysis which needs to be finished in a few days.</p>
<p>First of all I have to say that I have not much knowledge of statistics and therefore have problems to understand most of the answers for similar questions.</p>
<p>My question is:</p>
<p>I have c... | g49471 | [
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0.024370940402150154,
-0.024338796734809875,
... |
<p>I'm investigating using a trimmed mean to measure the location of various distributions. The distributions sometimes are heavily contaminated and sometimes not. Usually they follow something similar to a log-normal or possibly mixed log-normal distribution, but often the data is "all over the place".</p>
<p>I've lo... | g61111 | [
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0.04619982838630676,
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-... |
<p>I've been working on the implementation of some unsupervised algorithms to find bivariate/ multivariate outliers. The output of the algorithms is a scoring rank. Also, I don't have any data classified as normal or outlier.</p>
<p>My question is: is there any test that I can apply to the score data? How do I find th... | g61112 | [
0.019936811178922653,
-0.04444523900747299,
0.005343906115740538,
-0.03423066437244415,
-0.015363702550530434,
-0.02049855887889862,
-0.006525975652039051,
0.002504354575648904,
-0.03509202226996422,
0.002002440392971039,
0.022844597697257996,
0.06421703845262527,
0.0029565568547695875,
0.... |
<p>I've read some introduction about different kernels for SVM. It seems RBF is a measure of point distance while the basic kernel (i.e. no kernel) splits the space by hyper-planes.</p>
<p>I could imagine that for a mix of features, some features should be treated with RBF and some with the basic kernnel.</p>
<p>Is i... | g48655 | [
0.016863347962498665,
0.031097544357180595,
0.0062934099696576595,
0.061357587575912476,
-0.013790587894618511,
-0.061267342418432236,
-0.002995236311107874,
0.021601080894470215,
-0.04359867051243782,
-0.0477667972445488,
0.0014845812693238258,
0.023747272789478302,
0.03628804162144661,
0... |
<p>A Poisson process has PDF</p>
<p>$$P(X=k)=\frac{e^{-\lambda t}(\lambda t)^k}{k!}$$</p>
<p>I'm trying to find an expression for:</p>
<ol>
<li>$E[X | \lambda, t]$</li>
<li>Confidence intervals (i.e. find $\delta$ such that $P(\bar{x}-\delta<X<\bar{x}+\delta)=c$ for some $c$)</li>
</ol>
<p>To find the expecta... | g47275 | [
0.007989319041371346,
0.0016959583153948188,
-0.034296538680791855,
-0.09220636636018753,
0.046090152114629745,
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0.03425827994942665,
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0.011399859562516212,
0.007562487851828337,
-0.... |
<p>Suppose you have vectors X and Y with covariance matrix
$V = \left( \begin{array}{cc}
A & B \\
B^T & C \end{array} \right)$. This <a href="http://en.wikipedia.org/wiki/Schur_complement#Applications_to_probability_theory_and_statistics" rel="nofollow">Wikipedia</a> article says that $Var(X | Y) = A - BC^{-1... | g61113 | [
0.024371400475502014,
-0.05660892650485039,
-0.006921109743416309,
-0.039189234375953674,
0.054337795823812485,
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0.06069105491042137,
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0.021599728614091873,
-0.0365312285721302,
0.03194040805101395,
-0.038859836757183075,
0.05113... |
<p>Given N sampled values, what does the "p-th quantile of the sampled values" mean?</p> | g48922 | [
-0.04421795904636383,
0.0042147389613091946,
-0.03322673961520195,
-0.06182350218296051,
0.03948543593287468,
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0.002253699116408825,
-0.013827263377606869,
-0.07352904975414276,
-0.026324277743697166,
0.004796095658093691,
0... |
<p>The number of sequences in my sequence data is about 5,000, and the sequence length is 1440. In order to reduce computational time to obtain an optimal matching pairwise matrix, I want to randomly select 5% of the sample. I would appreciate your suggestions on that.</p> | g61114 | [
-0.02317279949784279,
-0.01318586990237236,
0.011606112122535706,
-0.012027601711452007,
-0.028895029798150063,
-0.12224314361810684,
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0.028233518823981285,
0.03970760479569435,
-0.015031256712973118,
-0.021875720471143723,
-0.02784884348511696,
... |
<p>Consider a t-test of means. One formula for computing the p-value assumes equal variances. Another formula assumes unequal variances. With small sample sizes the tests can give quite different results and one can examine the variances to see which assumption is more prudent. An alternative would be to compute the... | g61115 | [
0.03423164039850235,
0.04434005543589592,
0.005699455738067627,
-0.06001150608062744,
-0.046170804649591446,
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0.011918434873223305,
-0.06317730993032455,
0.016060901805758476,
0.018752507865428925,
0.001856453949585557,
0.05560136213898659,
0.04... |
<p>Any recommendations for easy to use and inexpensive software for conjoint analysis? I took graduate level stats more than a decade ago and would prefer something relatively easy to handle. </p> | g17566 | [
0.043661199510097504,
-0.032655008137226105,
0.018716316670179367,
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0.07224436104297638,
0.01313789002597332,
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-0.013904213905334473,
0.03522771596908569,
-0.04622778668999672,
0.008468745276331902,
0.02... |
<p>Why is it SVM computation cost does not depend on kernel value, dimensions (when separating hyperplane )? Is it because all it does is just classifying and
not much calculation involved?</p> | g17568 | [
0.040800973773002625,
0.09706395119428635,
0.01783759519457817,
0.03995763882994652,
-0.03516197204589844,
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0.03311053663492203,
0.018390363082289696,
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-0.024666527286171913,
0.030926765874028206,
-0.023544834926724434,
0.0706745907664299,
0.071637... |
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