question stringlengths 37 38.8k | group_id stringlengths 2 6 | sentence_embeddings listlengths 768 768 |
|---|---|---|
<p>Really struggling with this please help.</p>
<p>Find MLE for p and c</p>
<p>\begin{equation}
\ {f}(x,p,c) = (1-p)^{x-c}p
\end{equation}</p>
<p>x=c,c+1,c+2,.....</p>
<p>p is between 0 and 1</p>
<p>c is element of the integers</p>
<p>I am more interested in the mle for c</p>
<p>For the mle of p is it fine to ju... | g67041 | [
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<p>When performing cross-validation or bootstrap re sampling to estimate the performance of some machine learning algorithm, one commonly records the mean and variance of the errors obtained in of all the trials. This is commonly used in model selection, such as choosing the simplest (or quickest to run) model whose me... | g67042 | [
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<p>Please could you someone help me to find online resources related to the topic of quality control (statistical process control)</p> | g67043 | [
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<p>I am trying to interpret the following definition:</p>
<pre><code>A non-degenerate distribution is a stable distribution if it satisfies the
following property:
Let X1 and X2 be independent copies of a random variable X. Then X is said to
be stable if for any constants a>0 and b>0 the random variable aX1... | g37647 | [
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<p>I'm doing some reading on topic modeling (with Latent Dirichlet Allocation) which makes use of Gibbs sampling. As a newbie in statistics -- well, I know things like binomials, multinomials, priors etc -- I find it difficult to grasp how Gibbs sampling works. Can someone please explain it in simple English and/or usi... | g67044 | [
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<p>For classifying a sequence of instances, are there any specific circumstances that make Hidden Markov Models (HMMs) more accurate than Conditional Random Fields (CRFs)? I have seen several papers that show CRFs outperforming HMMs, but none showing the reverse (granted, my sample size is fairly small so far).</p>
<... | g26401 | [
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<p>This is a very silly question, however, it confuses me a lot! </p>
<p>Let's suppose that each observation consists of the prob of $A$ and the prob of $B$, with values $1/2$ and $1/2$ respectively. Also, let's assume that the global weight for $A$ (i.e. the mean of all observations for $A$) is $3/4$ and for $B$ is $... | g67045 | [
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<p>Could any one give me some hints for the following problem:
A coin has two face: 1 and -1/2, and the probability for 1 is $P(x=1)=1/3$ and for $-1/2$ is $P(x=-1/2)=2/3$. The expected value is therefore $E(x)=1\cdot(1/3)+(-1/2)\cdot(2/3) = 0$.<br>
Supposing for an infinite tossing, what's the chance that the average... | g67046 | [
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<p>I am trying to get the joint PDF of two RVs $X$ and $Y$ where $aX<Y<bX$, so I am stuck in calculating the probability of</p>
<p>$\mathbb{P}(X<x,Y<y|aX<Y<bX)$</p>
<p>any idea?</p> | g26402 | [
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<p>I realize that similar questions have already been asked and answered, but I am in need of a bit more detail and specific advice as I am new to PCA and statistical methods in general. My question is also a bit broader because I will be putting it in context and I need to know if I'm even headed in the right directio... | g211 | [
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<p>My supervisor asked me to find out which distribution represents a particular situation.</p>
<p>I have a VoIP generator that generates calls "uniformly" distributed between callers. This means that the volume per caller distribution is "almost" uniformly distributed between a minimum and maximum. So by running a te... | g49765 | [
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<p>I want to graphically show the change in relative risk along with confidence limits over 17 years. </p>
<p>Can I use a forest plot without meta-analysis because it will have the added advantage to tabulate Z-values and p-values also? Here I want to show the progressive change in the relative risk and NOT meta-analy... | g67047 | [
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<p>My knowledge is severely lacking when it comes to statistics..</p>
<p>I have qPCR data at different times after induction and I don't know what kind of statistics to use on it. I have values for 9 genes at 6 different time points from 2 different mutants and I want to show for every gene if there is a change over t... | g67048 | [
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<p><strong>My goal is to create CI for the CART prediction of new_x</strong></p>
<p>Consider the following code:</p>
<pre><code>require(rpart)
set.seed(147830)
n <- 100
x1 <- runif(n)
x2 <- rnorm(n)
y <- x1 + 2*x2 + rnorm(n, 0, .5)
DAT <- data.frame(y,x1,x2)
fit <- rpart(y ~ x1 + x2, data = DAT)... | g67049 | [
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<p>I am planning to develop a new tool and planning to use it across 4 countries. For the tool validation, is it right to include sample from very large population of 4 countries? Will it affect the normality of the distribution of data and tamper the data analysis process? </p>
<p>Is it important that the sample need... | g67050 | [
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<p>I followed a course on machine learning.</p>
<p>The analysis of learning curves on the cross-validation set was recommended, as a way to see in what respect your model can be improved (more data, more features etc.).</p>
<p>Does anybody know if SPSS supports the analysis of learning curves?</p> | g67051 | [
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<p>I'm learning about Markov Chain Monte Carlo methods, and to my undifferentiated mind, they basically resemble gradient descent with a stochastic component replacing the gradient computation. Is this a correct understanding. If not what key difference am I missing?</p> | g67052 | [
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<p>I'm a little new to data mining and would definitely appreciate some tips.
I'm using clustering algorithms looking for possible grouping in some variables described below.
I've been using the Excel data mining add-in which connects to SSAS and uses the EM algorithm by default. I'm also using R, so far with the Kmea... | g67053 | [
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<p>What is relationship between "significant correlation" and "significant difference" between two variables?</p> | g67054 | [
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<p>My data basically includes a number of ordinal (and some nominal) variables on perceptions of volunteers. I essentially want to see whether perceived personal benefit from volunteering (based on a Likert scale) is dependent upon certain factors, such as whether they were a good teacher (also an ordinal Likert scale)... | g67055 | [
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<p>I've been toying around with logistic regression with various batch optimization algorithms (conjugate gradient, newton-raphson, and various quasinewton methods). One thing I've noticed is that sometimes, adding more data to a model can actually make training the model take much less time. Each iteration requires ... | g67056 | [
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<p>There were several samples BLQ because of the lower limit of quantitation (LLQ) of the method, e.g. 5 ng/ml or less. Using the statistical program PRISM6 I marked these values together with the outliers (determined with the Rout method, 1% rule, before doing the calculations).
The question was raised by the laborato... | g67057 | [
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<p>I would be using such software to run multiple regressions using macroeconomics variables as independent variables to estimate other macroeconomic ones as single dependent variables.</p>
<p>I need to be able to run robust regressions including Weighted Least Squares(to resolve heteroskedasticity), Feasible Generali... | g67058 | [
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<p>I'm trying to justify using of GLM model in my project instead of a simple linear regression. A lot of sources that I've seen contain the statement that "GLM allow us to build regression models for response variables that are not normally distributed". I can't understand what that is supposed to mean since we don't ... | g67059 | [
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<p>I've been reading about the Dvoretzky-Kiefer-Wolfowitz inequality, in the context of confidence bands on empirical distribution functions.</p>
<p>I think I understand the inequality at face value: that the probability that the empirical distribution function differs from the real distribution function by more than ... | g40435 | [
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<p>I am having a problem using the <code>2l.norm</code> method of multilevel imputation in <code>mice</code>.</p>
<p>Unfortunately I cannot post a reproducible example because of the size of my data - when I reduce the size, the problem vanishes.</p>
<p>For a particular variable, <code>mice</code> produces the follow... | g67060 | [
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<p>This is a bit of an elaboration on a <a href="http://stats.stackexchange.com/questions/55778/equivalent-to-k-s-test-on-discrete-data-with-uneven-quantization">question I posted earlier</a>, since I feel like my approach to the problem as a whole is probably quite flawed.</p>
<p>Suppose I have a set of treatment and... | g67061 | [
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<p>I am interested in getting an unbiased estimate of $R^2$ in a multiple linear regression.</p>
<p>On reflection, I can think of two different values that an unbiased estimate of $R^2$ might be trying to match. </p>
<ol>
<li><strong>Out of sample $R^2$:</strong> the r-square that would be obtained if the regression ... | g40523 | [
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<p>for $N$ samples of two correlated random variables $X \sim N\left(0,\sigma_X^2\right)$ and $Y \sim N\left(0, \sigma_Y^2\right)$ with correlation $\rho$, I am analyzing the ratio of the sample variances, $r=\frac{s_Y^2}{s_X^2}$. Currently, I am foccusing on $E\left[r\right] = E\left[\frac{s_Y^2}{s_X^2}\right]$.</p>
... | g26417 | [
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<p>I've done quite some reading on multiple imputation (MI), but can not seem to figure out the next question:</p>
<p>I have a dataset with missing values, some rows have many missing values, others have less missing values. They are missing at random.</p>
<p>I want to exclude certain rows because there are missing t... | g26418 | [
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<p>I found an interesting problem in a contest on temperature prediction:
<a href="https://www.hackerrank.com/contests/expansion-challenge/challenges/temperature-predictions" rel="nofollow">https://www.hackerrank.com/contests/expansion-challenge/challenges/temperature-predictions</a></p>
<p>It is not about forecasting... | g67062 | [
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... |
<p>I am using scikit-learn Multinomial Naive Bayes classifier for binary text classification (classifier tells me whether the document belongs to the category X or not). I use a balanced dataset to train my model and a balanced test set to test it and the results are very promising.</p>
<p>This classifer needs to run ... | g67063 | [
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<p>Having built a regression model with an ordinal response variable and predictors comprised of categorical and continuous nature, I have some questions that pertain to one of the final goals, i.e. suggest another class for certain observations (which ones is unknown) in the training set. I approach this problem with ... | g67064 | [
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<p>I read a lot of evolutionary/ecological academic papers, sometimes with the specific aim of seeing how statistics are being used 'in the real world' outside of the textbook. I normally take the statistics in papers as gospel and use the papers to help in my statistical learning. After all, if a paper has taken years... | g67065 | [
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... |
<p>I am trying to learn a linear regression model. However, I have some confusion related to the normalization of the data. I have normalized the features/predictors to zero mean and unit variance. Do I need to do the same for the target. If so why?</p> | g67066 | [
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<p>I know, that the white noise is called "white noise", because it comes from physics and has something to do with the spectral decompoistion (is that right?) of the white light? I am not familiar with signal theory, so could anyone explain me why it is called white noise, especially the relation to the terms light, s... | g26420 | [
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<p>I have a sample from an unknown distribution. I checked with KS test the hypotheses that the sample represents lognormal, Weibull or Rayleigh distributions and the test shows that all these hypotheses cannot be accepted.</p>
<p>Are there any means to find the distribution that approximates my sample in the best way... | g14 | [
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<p>I understand that we use random effects (or mixed effects) models when we believe that some model parameter(s) vary randomly across some grouping factor. I have a desire to fit a model where the response has been normalized and centered (not perfectly, but pretty close) across a grouping factor, but an independent v... | g37912 | [
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<p>I have a confusion related to the dual of svm</p>
<p>In the main objective function I have</p>
<p><img src="http://i.stack.imgur.com/qNxtL.png" alt="enter image description here"></p>
<p>Now to solve the dual of this objective function, I will minimize with respect to the primal variables first to get </p>
<p><i... | g67067 | [
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0... |
<p>Say I have the following simple Bayesian network involving 3 r.v.s A, B, and C:</p>
<p>$$
A \rightarrow C \rightarrow B
$$</p>
<p>I am trying to prove that A and B are conditionally independent given by marginalizing out C and seeing if I get out $p(a, b) = p(a)p(b)$ in</p>
<p>$$
p(a, b) = p(a) \sum_{c} p(b|c)p(c... | g46893 | [
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<p><em>(I have no real idea what to tag this with because I'm no statistician and I don't know what field this falls into. Feel free to add more suitable tags.)</em></p>
<p>I work for a company that produces data analysis software, and we need a decent set of data to test and demo our latest product with. We can't jus... | g26423 | [
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<p>I have acquired data from 3 different donors in which 6 different drugs were tested over a period of time. For a period of 1 week I have measured 1 parameter each day from each condition from each donor.</p>
<p>I would like to compare two drugs with one and other. But when I plot the parameter values over time of e... | g67068 | [
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<p>i got a problem with cross-validation!</p>
<p>I got two studies, t(N=1200) and t+1(N=200) respectively. The 200 corporations form t+1 are also part of the t0-Data. In t+1, there are two significant relationships using kendall's tau, but they are unexpected relationships. In order to check for errors, i want to do a... | g26425 | [
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... |
<p>Why are my confidence intervals performing so poorly?</p>
<p>I have a data frame <code>may</code> of two variables $C$ and $F$. I perform a linear regression</p>
<pre><code>lm.1 <- lm(may$C ~ may$F)
lm.1$coef[2]
# may$F
# 0.0161821
confint(lm.1)[c(2,4)]
# [1] 0.0151 0.0173
</code></pre>
<p>So far so g... | g67069 | [
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0.008604937233030796,
-0.0... |
<p>Say I have a set of data which I know comes from a Binomial distribution (generated using the <code>rbinom</code> function in <code>R</code>).</p>
<p>Is there any way to use the data to work backwards and work out the <code>p</code> and <code>n</code> parameters of the Binomial distribution from which it came?</p>
... | g46895 | [
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-0.... |
<p>This question might be very basic, but somehow I don't understand this point.</p>
<p>Suppose initially I used a univariate regression equation such as</p>
<pre><code>GDP=a+b*Income
</code></pre>
<p>I'll get some coefficient values (say 0.5). Now, I'm using the same structure of the regression model, but added a... | g49674 | [
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-... |
<p>I would like to know more details about R issues mentioned in <a href="http://www.stat.pitt.edu/stoffer/tsa3/Rissues.htm" rel="nofollow">Time Series Analysis and Its Applications: With R Examples</a>. </p>
<p>For e.g. the first problem still exists in R version 3.0.1</p>
<pre><code># generate an AR(1) with mean 50... | g26429 | [
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0.024706905707716942,
-0.00... |
<p>I'm looking for non-linear regression analysis references. </p>
<p>I'll be grateful if somebody can give me some references.</p> | g26431 | [
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0... |
<p>I have some survey data and employees are divided into grades (from 1 to 7). At first glance, this appears to be a continuous variable. However, based on my knowledge of the organization, I know that levels 5 and above are managers, while those in grades 1 to 4 are lower level employees. From this variable, I would ... | g67070 | [
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0.008344081230461597,
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<p>The MARSS package in R offers function for dynamic factor analysis. In this package, the dynamic factor model is written as a special form of state space model and they assume the common trends follow AR(1) process. As I am not very familiar with those two methods, I come with two questions:</p>
<p>Is the Dynamic F... | g26432 | [
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0.... |
<p>I am building a predictive model. I split 2/3 of the data into a training set, and the rest into the test set. I build a model based on the training set. I use the the model to test on the training set, and the test set.</p>
<p>What are the advantages and disadvantages to iterating through all 3 combinations of t... | g67071 | [
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<p>I remember seeing/reading somewhere that for multiclass SVMs with unbalanced data, there was a way to determine the class weights from the training data (rather than X validation). Does anyone know what the method is or what paper its from?</p>
<p>Thanks</p> | g67072 | [
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... |
<p>I want to know the approaches people use to forecast lets say unemployment rate .... By itself it might not fit a time series model (ARMA) very well as the trend is dependent on many external factors. </p>
<p>My hypothesis is that if a time series for the target doesn't fit well, but some of the underlying causal v... | g67073 | [
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<p>How should I calculate sample size for a clinical trial when I need a power of 80% and I predict an effect size to be at lest 0.5? do I need to estimate the mean of outcome as well?</p> | g67074 | [
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<p>Suppose $X \sim U(0,1)$, and $Y[x] = g(x)$ where $g(.)$ is some complicated function. I want to calculate/plot the density of $Y$. I can do this analytically for simple enough $g$.</p>
<p>I can also generate some large number $N$ samples of $X$ from the stardard uniform, calculate $y_i = Y(x_i)$ for each sample $x_... | g26436 | [
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0.... |
<p>I've used Stata 12 to estimate a hierarchical logit model (xtmelogit) with random intercepts. The outcome is incarceration (1=yes) for a series of convicted criminal offenders. There are a slew of interaction terms and I'm trying to understand these by looking at the predicted odds at different levels of X while h... | g46903 | [
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<p>I am having some trouble trying to decide what measure of inter-rater reliability to use in a study. Part of a larger study involves accurately determining when participants began (onset) and stopped (offset) writing. I have video footage which captures the writing, and can determine the time of onset/offset to th... | g67075 | [
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0.001329199643805623,
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0.0... |
<p>While building a regression model in R (<code>lm</code>), I am frequently getting this message</p>
<pre><code>"there are aliased coefficients in the model"
</code></pre>
<p>What exactly does it mean?</p>
<p>Also, due to this <code>predict()</code> is also giving a warning.</p>
<p>Though it's just a warning, I wa... | g26442 | [
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<p>In studying the relationship between income and consumption, it is common to sort the observations by income and observe that high-income households have lower levels of consumption per dollar of income than low-income households, i.e., they have higher savings rates. This conforms to one's naive intuitions about th... | g47007 | [
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<p>I am trying to work on a process to improve how how well my team estimates. I want to look at using some statistics to help out and embrace the uncertainty in how we estimate tasks.</p>
<p>If I have a group of experts and I ask them for a best (b), average (a) and worst (w) case estimate for a task, creating a tria... | g67076 | [
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<p>A simple question to which I don't seem to find the answer anywhere. </p>
<p>I have a response variable <code>duration of time spent doing A</code> of individuals tested for $\text{max duration}=X$. Therefore the variance is likely to be much wider at $x=0.5$ compared to $X=0$ and $X=1$. </p>
<p>However, I am conf... | g17300 | [
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<p><a href="https://en.wikipedia.org/wiki/Binary_relation">A relation between two sets</a> can be visualized with a grid-like table in which the rows are labelled along the left with the elements of one set and the columns are labelled along the top with the elements of the other, and in which each cell of the table is... | g67077 | [
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0.05569908395409584,
-0.012... |
<p>I was reading on the computation of the unbiased estimation of standard deviation and the source I read stated </p>
<blockquote>
<p>(...) except in some important situations, the task has little relevance to
applications of statistics since its need is avoided by standard
procedures, such as the use of signif... | g26445 | [
0.02610253356397152,
0.04393425211310387,
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-0.028606606647372246,
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0.016263917088508606,
0.039887189865112305,
-... |
<p>I would like to use a log-log model and one of my independent variables is log (investment in machinery/employee).</p>
<p>Some firms report 0 investment. I have to take logs and I would like to know which approach is most approriate:</p>
<ol>
<li><p>take log(investment in machinery/employee) and set log(0)=0 and a... | g49766 | [
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0.03926638141274452,
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-0.00... |
<p>I came across this "concordance score" in a set of slides called <a href="https://conference.stat.osu.edu/nssl2010/slides/Zhu_Sat_100.pdf" rel="nofollow">Penalized regression methods for ranking variables by effect size, with applications to genetic mapping studies</a>, by Ji Zhu:
$$
\mathrm{CS} = \frac{ \sum_{j \ne... | g67078 | [
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0.09039291739463806,
0.07354404777288437,
-0.0... |
<p>I was working on a research project in which I try to estimate the the individual contribution of a group of regional political leaders to local economic growth. The major challenge is that there is relatively few locality-year observations to the number of regional leaders. Overall I have about 300 political leader... | g67079 | [
0.04561123996973038,
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0.044857531785964966,
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0.014357618987560272,
0.05866532400250435,
0.01... |
<p>I'm using R to develop regression models, and I need to compare two different models' performance. The question that arises is, "Is Model 1 statistically better than model 2?" and I don't seem to have a way to answer that question.</p>
<p>Background: Model 1 consists of Variable A regressed on the endpoint. Model 2... | g67080 | [
0.03414555639028549,
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0.04014011472463608,
0.0620436817407608,
-0.002... |
<p>My larger question is what might be the best analytical approach given the structure of my data (see data summary below) but presently, I'm wondering if the normality of the model residuals are normal enough to justify a linear mixed model or should I pursue a glmm? I did build lmm and glmm models and couldn't get ... | g67081 | [
0.00009177441097563133,
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0.001627960242331028,
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0.001595551846548915,
0.04311949759721756,
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0.020823096856474876,
-0... |
<p>I once heard the following statement:</p>
<blockquote>
<p>The PACF (partial autocorrelation function) for MA processes behaves
much like the ACF for AR processes; the PACF for AR processes behaves
much like the PACF for AR processes.</p>
</blockquote>
<p>How to understand the logic underlying this statement... | g67082 | [
0.09840397536754608,
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0.012867073528468609,
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0.03220672532916069,
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0.001663055270910263,
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-0.05123664811253548,
-0.017615143209695816,
0.047771912068128586,
0.07864272594451904,
-0.0... |
<p>Consider the simple pmf:</p>
<p>$$p_n (x)=\begin{cases} 1\quad x=2+1/n \\ 0\quad \text{elsewhere} \end{cases}$$</p>
<p>Then my book states that $\lim_{n\to \infty} p_n (x)=0$ <strong>for all values of $x$</strong>. Is that really the case though? Why can we not say that the probability of $x=2$ equals $1$ as $n \t... | g7759 | [
0.03049568645656109,
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0.016925381496548653,
0.013783896341919899,
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0... |
<p>Lets say I have a sample data (here is just 10 numbers, in real I have about 10000 measurement results). Then, I want to check if the data is stationary or not using Simple Average Method. For example, my data set of size <code>N = 10</code>:</p>
<pre><code>X = {1.0, 2.0, 3.0, 4.0, 5.0, 6.0, 7.0, 8.0, 9.0, 10.0};
<... | g26452 | [
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0.0028511551208794117,
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0.060608960688114166,
-0.011874246411025524,
... |
<p>I have a survey where I have asked people which type of computer games they enjoy and whether they consider themselves a hardcore gamer. I allowed people to select multiple genres, but now I am unsure what to do with my data.</p>
<p>I initially thought factor analysis, with the idea being if there were genres that ... | g67083 | [
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0.04472329095005989,
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0.... |
<p>I have the data of how many users post how many questions. For example,
[UserCount, QuestionCount]
[2, 100]
[9, 10]
[3, 80]
... ...</p>
<p>it means each of the 2 users posts 100 questions, each of the 9 users posts 10 questions, and so on. So, how to validate whether the UserCount-QuestionC... | g67084 | [
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0.06286153942346573,
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0.03375127166509628,
-0.01989414170384407,
0.013997775502502918,
0.0... |
<p>When transforming variables, do you have to use all of the same transformation? For example, can I pick and choose differently transformed variables, as in: </p>
<p>Let, $x_1,x_2,x_3$ be age, length of employment, length of residence, and income.</p>
<pre><code>Y = B1*sqrt(x1) + B2*-1/(x2) + B3*log(x3)
</code></pr... | g26455 | [
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0.004102899692952633,
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0.04072459042072296,
0.003107447177171707,
... |
<p>Full Disclosure: This is homework. I've included a link to the dataset ( <a href="http://www.bertelsen.ca/R/logistic-regression.sav">http://www.bertelsen.ca/R/logistic-regression.sav</a> )</p>
<p>My goal is to maximize the prediction of loan defaulters in this data set. </p>
<p>Every model that I have come up wit... | g26456 | [
-0.021477703005075455,
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0.035990919917821884,
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-0.0013725414173677564,
0.017080597579479218,
0.05066172778606415,
0.04100911691784859,
... |
<p>In SPSS output there is a pretty little classification table available when you perform a logistic regression, is the same possible with R? If so, how?</p>
<p><img src="http://i.stack.imgur.com/yFS6P.jpg" alt="alt text"></p> | g46937 | [
0.028495145961642265,
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0.05975443497300148,
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0.010... |
<p>One of the assumptions for using the Wilcoxon sign-rank test is that the underlying distribution is continuous (<a href="http://en.wikipedia.org/wiki/Wilcoxon_signed-rank_test#Assumptions" rel="nofollow">see here</a>.)</p>
<p>However, there are cases (for example, when analyzing Likert scale data) where this assump... | g67085 | [
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-0.051611125469207764,
0.004544478841125965,
0.058527518063783646,
-0.028999732807278633,
... |
<p>I have some functions of $x$, in the form of $d\sqrt{x}$ or $d\log(x)$ where $d$ is known. I would like to rewrite (approximate is fine) them in the form $a/(1 + bx^c)$, where $a$, $b$ and $c$ are arbitrary.</p>
<p>I don't think there are $a$, $b$ and $c$ such that the two curves will match exactly, so I think mayb... | g26459 | [
0.00899563729763031,
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0.014640426263213158,
-0.02153552882373333,
0.027658183127641678,
0.06147260591387749,
0.... |
<p>I am using this for a reliability analysis test for quantitative values between two raters. I got my results using the "relInterIntra {irr}" package in R, but the reported values gave me several "rhohat" values. I am unsure which co-efficient the results represent. Could someone help enlighten me here? I am new to u... | g67086 | [
-0.005641650408506393,
-0.04852820560336113,
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0.0433039553463459,
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0.022068550810217857,
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0.... |
<p>I'm fitting a classifier with cross-entropy loss (i.e. Bernoulli likelihood). Some examples are very clearly associated with one class or the other, and despite some attempts at regularization, the classifier sometimes assigns probabilities $<10^{-9}$.</p>
<p>While the true probability might actually be this sma... | g26462 | [
0.035501062870025635,
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0.03495775908231735,
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0.029383176937699318,
-0.02273721620440483,
0.010585370473563671,
0.027956094592809677,
0.03... |
<p>Is there any nonparametric version of ANOVA able to deal with multiple factors AND evaluate their interaction(s)?</p>
<p>If the interactions are really impossible to evaluate, is there any generalization of the Friedman test to more than two factors?</p> | g67087 | [
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0... |
<p>I am learning multiple regression with categorical variables and in a book I came across this problem. </p>
<p>For yield of corn suppose there are two factors affecting, nitrogen level and depth of ploughing. Say there are three nitrogen categories(1,2,3) and two depth categories(1,2). </p>
<p>There's a interact... | g67088 | [
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0.012732153758406639,
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-0.0171730387955904,
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0.024473411962389946,
0.004539634566754103,
0.01... |
<p>I am trying to use <strong>Information Gain</strong> to select features when classifying text with a Support Vector Machine.</p>
<p>For each word in our training data, we computed its information gain. Then, we should keep only the words with an IG superior to some threshold. </p>
<p>When reading the litterature a... | g67089 | [
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0.02021898329257965,
0.009749984368681908,
0.009273973293602467,
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0.08076149225234985,
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0.0059437560848891735,
0.0015100312884896994,
0.033817216753959656,
0.018060781061649323,
0... |
<p>I am running a multinomial logistic regression with SPSS and I have encountered a problem (?) with my data. I have a dependent variable (DV) with three categories, five independent variables (IV) as factors and four IVs as covariates. There are close to 4800 respondents in the data. </p>
<p>The distribution of my D... | g26466 | [
0.003207232803106308,
-0.014071306213736534,
-0.010794388130307198,
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0.03484899923205376,
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0.004070450086146593,
0.006911948788911104,
0.012077080085873604,
0.028012610971927643,
-... |
<p>I just touched Gaussian processes two weeks ago. I am not very familiar with the selection of a model and its hyperparameters. Here is the demo code that I run for a 2-D Gaussian processes regression. Its output is not what I expected.</p>
<pre><code>% produce the training set for regression.
% Here, the regression... | g560 | [
-0.0024819127283990383,
-0.033208783715963364,
0.01926491968333721,
-0.037785641849040985,
0.013364261016249657,
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0.0430537685751915,
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0.0012317841174080968,
-0.08838707208633423,
-0.017556462436914444,
0.08341486752033234,
0.02880946733057499,
0... |
<p>Apologies for the rudimentary question, I am new to this form of analysis and have a very limited understanding of the principles so far.</p>
<p>I was just wondering if many of the parametric assumptions for multivariate/univariate tests apply for Cluster analysis? Many of the sources of information I have read reg... | g67090 | [
0.0055554211139678955,
0.01264667697250843,
0.015723932534456253,
0.02647135965526104,
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0.035524267703294754,
0.01947202906012535,
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0.005900160875171423,
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0.031718455255031586,
0.0... |
<p>I am trying to test if there has been a significant change in the weight of two groups, one without exercise and one with exercise. </p>
<p>The two samples have large spread, which creates a standard deviation that is larger than the mean for each group. </p>
<p>My question is, is it still valid to use the unpaire... | g67091 | [
0.005621986463665962,
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0.03334638103842735,
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0.01161868218332529,
-0.012622436508536339,
0.05367601290345192,
... |
<p>Let's say in an experiment, the Null hypothesis is patients having Condition $\alpha$ (type I error) is $0.05$ and $\beta$ (type II error) is $0.15$. </p>
<p>If I have a sample of 50 patients, 35 with condition A and 15 with condition B, how would I work out the following:</p>
<ol>
<li>Probability of properly pred... | g46949 | [
0.03535874933004379,
-0.01720617339015007,
0.031547583639621735,
-0.018368899822235107,
0.02528449147939682,
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0.018173053860664368,
0.06042170897126198,
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-0.007041949778795242,
0.04923437535762787,
0.03452879562973976,
0.036025270819664,
-0.04404103... |
<p>My end goal is to present the average travel time for a corridor and the standard deviation (or standard error) of that travel time. I'm not sure what to present to be statistically correct, here is the information I have to summarize:</p>
<p>I have the average travel time for a segment of road for a specific windo... | g67092 | [
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0.00618703430518508,
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0.031335532665252686,
0.01947924681007862,
0.02883218415081501,
0.04548293352127075,
-0.06854762881994247,
0.058029379695653915,
-0.0... |
<p>For a variable $B\sim \textrm{Bin}(p,n)$. I observe $m$ successes. I know I can estimate $\hat{p}$ with</p>
<p>$$\hat{p} = \frac{m}{n}$$</p>
<p>and I can approximate the CI by using a normal approximation by CLT where I assume</p>
<p>$$p\sim\mathcal{N}\left(\hat{p}, \frac{\hat{p}(1-\hat{p})}{n}\right)$$</p>
<p>H... | g67093 | [
-0.011336897499859333,
0.01316082663834095,
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0.026873202994465828,
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0.0898720771074295,
-0.03141455352306366,
0.00... |
<p>When testing some null versus alternative hypotheses by a test statistic $U(X)$, where $X = \{ x_i, ..., x_n\}$, apply the permutation test with the set $G$ of permutations on $X$ and we have a new statistic
$$
T(X) := \frac{\# \{\pi \in G: U(\pi X) \geq U(X)\}}{|G|}.
$$</p>
<ol>
<li><p>What is the benefit of using... | g67094 | [
0.023212980479002,
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0.006586899980902672,
0.020183835178613663,
0.0175842996686697,
0... |
<p>Suppose there are more than two random variables $X_1, X_2, \dots, X_n$.</p>
<p>Can mutual independence between them be defined in terms of conditional distributions?</p>
<p>Thanks!</p> | g67095 | [
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-0.03084251470863819,
... |
<p>I am regressing firm characteristics on some stock trading-related measures in a panel dataset. Firm size is a highly significant control variable, independent of the estimation method etc. My focus variables are related to firm size though, either by construction (e.g. $focus variable = x / firmsize$) or because of... | g67096 | [
0.03808123618364334,
0.020642513409256935,
0.01044572051614523,
-0.02687503769993782,
-0.015662522986531258,
-0.06960298120975494,
-0.011285490356385708,
0.004499711561948061,
0.009740160778164864,
-0.033883240073919296,
0.040572911500930786,
0.002227322431281209,
0.012925483286380768,
0.0... |
<p>I'm going to do a multiple regression analysis with two continuous IVs and their interaction. I've centered the IVs and then multiplied one with another for interaction. My problem is that the interaction variable is severely kurtotic (kurtosis 7,731, standard error=0,127, z=60.87). How should I deal with this? Remo... | g26475 | [
0.0515153668820858,
-0.025023415684700012,
0.009072677232325077,
0.0058457814157009125,
-0.009950019419193268,
-0.01519734039902687,
0.0010877378517761827,
0.03861413151025772,
-0.013000168837606907,
0.016101883724331856,
-0.012391798198223114,
0.010086015798151493,
0.006026637274771929,
-... |
<p>I solve Rubik's cubes as a hobby. I record the time it took me to solve the cube using some software, and so now I have data from thousands of solves. The data is basically a long list of numbers representing the time each sequential solve took (e.g. 22.11, 20.66, 21.00, 18.74, ...)</p>
<p>The time it takes me to... | g67097 | [
-0.006562618538737297,
0.03456889092922211,
-0.005061465781182051,
0.007741335313767195,
-0.007335067726671696,
-0.07020840048789978,
0.05991882085800171,
0.0007528488640673459,
-0.016126660630106926,
-0.016087843105196953,
-0.01216169074177742,
0.054562658071517944,
0.04587932676076889,
0... |
<p>In my research paper, I wish to compare the accuracy of 2 clustering algorithms. I have conducted clustering using these 2 algortihms on 300 proprietary datasets. I use <a href="http://en.wikipedia.org/wiki/Rand_index#Adjusted_Rand_index" rel="nofollow">adjusted rand index</a> as the evaluation metric. Since, cluste... | g26479 | [
0.01995234563946724,
-0.027112949639558792,
-0.010462498292326927,
-0.06863151490688324,
0.01534681674093008,
-0.03695666417479515,
0.013421452604234219,
-0.003920115064829588,
-0.03480872884392738,
0.02514365315437317,
0.09031567722558975,
0.016549937427043915,
0.0670388713479042,
-0.0063... |
<p>I am working with SEM and would like to know how I could conduct a market segmentation test. I am trying the same model on two different samples and would like to test whether it's better to have them modeled separately or modeled as one bigger sample.</p>
<p>Can anyone help me with this?</p>
<p>Thank you,
Deuteri... | g67098 | [
-0.009114544838666916,
0.009871562011539936,
0.006722422316670418,
-0.024145539849996567,
0.02347278594970703,
-0.024462053552269936,
-0.024690574035048485,
0.013067842461168766,
0.011139605194330215,
-0.005876969080418348,
0.03447752445936203,
-0.017531773075461388,
0.04900830239057541,
0... |
<p>I have data showing outcomes of some treatment on different people grouped by sex and age (grouped into: infant, child, adult). I need to investigate if there is any difference in outcome among age groups or between sexes.</p>
<p>I used:</p>
<pre><code>model <- aov(data$outcome ~ data$sex*data$age)
summary(mode... | g67099 | [
-0.0678681954741478,
0.034366413950920105,
0.007926001213490963,
-0.07328853756189346,
-0.012927049770951271,
0.002099096542224288,
0.0296593327075243,
-0.01558149978518486,
-0.04577479884028435,
0.014533293433487415,
0.035880256444215775,
-0.0017679043812677264,
0.061594534665346146,
-0.0... |
<p>$\newcommand{\X}{\mathbf{X}}
\renewcommand{\S}{\mathbf{S}}
\newcommand{\I}{\mathbf{I}}
\newcommand{\1}{\mathbf{1}}
$
I found an <a href="http://www.econ.uzh.ch/faculty/wolf/publications/jef.pdf" rel="nofollow">article</a> with an unusual (for me) covariance matrix.</p>
<p>Let $\X$ denote an $N\times T$ matrix of $... | g67100 | [
-0.02449893020093441,
0.01357506774365902,
-0.0360742025077343,
-0.048167772591114044,
0.024944357573986053,
0.007044496946036816,
0.044146984815597534,
-0.036795709282159805,
-0.01834651455283165,
-0.0027341537643224,
0.01687769405543804,
0.05281902477145195,
-0.039730969816446304,
0.0496... |
<p>Other than a calibration plot, is there a way to decide how good one models' predictive probabilities as compared to another model. </p>
<p>I'm not interested in error rates as I find them ineffective for the level of precision I'm looking for. </p>
<p>The only quantity of interest is the predictive probability di... | g67101 | [
-0.0009488454670645297,
-0.0326656810939312,
0.020795784890651703,
0.013666709885001183,
0.033747781068086624,
-0.057100873440504074,
0.00330179906450212,
0.00860657636076212,
-0.014010044746100903,
-0.04015001282095909,
0.04227634146809578,
0.022311773151159286,
0.08338488638401031,
-0.02... |
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