question stringlengths 37 38.8k | group_id stringlengths 2 6 | sentence_embeddings listlengths 768 768 |
|---|---|---|
<p>I use GLMM and LMM to find significant factors for my data. And could I ask if the results from these two models already give me planned contrasts? Or do I need to run them separately?</p> | g62142 | [
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... |
<p>$s^2 = \sum \frac{(x_i - \bar{x})^2}{n-1} $ which apparently equals $ \frac{\sum(x_i^2) +n\bar{x}^2 - 2n\bar{x}^2}{n-1}$. Does this just come from expanding the numerator and using the fact that $\bar{x}$ (the average) is not dependent on $i$? How might one continue this to show for certain $E(s^2) = \sigma^2$?</p> | g49636 | [
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<p>I'm dealing with spatial data where the response variable is the gas concentration. In addition, I've the x,y-coordinate values, and another covariates. I'm thinking to fit a Gaussian random field model as follows:</p>
<p>$$ Z(s) = X(s) \beta + \epsilon(s) $$</p>
<p>where $ [Z(s) : s \in R^2]$, $X(s)$ is a set of ... | g62143 | [
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... |
<p>I am using glmnet for LASSO. My data set contains several continuous variables and one categorical variable (it has four levels). I wondered if I could treat three dummy variables as other continuous variables. Should I use a type of group LASSO approach for the three dummies? I'm sorry if this is a dumb question.</... | g62144 | [
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<p>I am confused about the difference between the <strong>nominal</strong> and the <strong>actual</strong> <a href="http://en.wikipedia.org/wiki/Coverage_probability" rel="nofollow">coverage probability</a>.</p>
<p>Say we are trying to estimate the fraction of the current population of the US that has been diagnosed w... | g62145 | [
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<p>For the two-variable case, what are the practical differences between using the Engle-Granger procedure versus the Johansen test for cointegration? Is one universally more powerful than the other? Will one give more false positives or false negatives than the other? Should Johansen always be preferred?</p> | g62146 | [
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<p>I have data that are non-normal and (strongly) negative skewed. The data also have high kurtosis and outliers. There appears to be a variety of options for transformation, but I cannot find a source that helps me determine the best option (or why to choose one over the other). In this case, should I </p>
<ol>
<li>... | g19105 | [
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<p>I am struggling to fit a simple logistic regression for one dependent value (group) by one independent qualitative variable (dilat) measured twice independently (rater).</p>
<p>I try many solutions and think according <a href="http://www.ats.ucla.edu/stat/mult_pkg/whatstat/" rel="nofollow">http://www.ats.ucla.edu/s... | g19106 | [
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... |
<p>I'm trying to build a regression model to predict subjective memory reports based on the following predictors: objective memory test, illness perceptions, verbal fluency, and mood. I also want to control for age, years of education and IQ by putting them into the regression model too. However, there's a problem. </p... | g19107 | [
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<p>I am comparing the relationship between genetic and geographic distance of individuals in a wild animal population. The hypothesis is that individuals with higher genetic relatedness establish home ranges closer to one another (shorter geographic distance between them) than to individuals that are less related (ie: ... | g62147 | [
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<p>In the following bioinformatics paper, <a href="http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2629784/" rel="nofollow">"Quantifying environmental adaptation of metabolic pathways in metagenomics"</a>, Gianoulis et al. employ the use of two tools to detect multivariate relationships between environmental features and m... | g62148 | [
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0.... |
<p>Does anyone know how to do post hoc tests in ANCOVA with a factorial design?</p>
<p>I have two vectors consisting of 23 baseline values (covariate) and 23 values after treatment (independent variable) and I have two factors with both two levels. I created an ANCOVA model and calculated the adjusted means, standard ... | g62149 | [
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<p>In Discovering Statistics Using SPSS 4e, Andy Field writes on p835 that:</p>
<blockquote>
<p>SPSS gives you the choice of two methods for estimating the parameters in
the analysis: maximum likelihood (ML), which we have encountered
before, and restricted maximum likelihood (REML). The conventional
wisdom se... | g62150 | [
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<p>I have seen it many times in a number of articles that nonparametric techniques are subject to the curse of dimensionality, which may lead to the failure of these methods. Why does this happen? Could give me an example? Thanks!</p> | g19111 | [
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<p>Lets say there is a theoretical relationship you want to prove over all values of some variable.
For example, $F(x)$ increases with $x$.</p>
<p>You are unable to come up with a general theoretical proof. However, you can calculate $F(x)$ for any specific value of $x$, and the expected relationship holds.</p>
<p>P... | g38221 | [
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<p>I just need a simple explanation of what exactly ridge regression is so I can have a decent intuitive understanding of it. I understand it's about applying some sort of penalty to the regression coefficients... but beyond that I'm a little confused about how it is different from other kinds of regression which imple... | g62151 | [
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<p>This is what is written in my notes. </p>
<blockquote>
<p>Constants are RVs: for $X=c=const$, one has $\{X \leqslant t\} = \begin{cases} \emptyset, t<c \\ \Omega, t \geqslant c\end{cases}$</p>
</blockquote>
<p>Why does the event $\{X \leqslant t\}$ is equal to the sample space when $t \geqslant c$ and $X=c$... | g19115 | [
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<p>I am a newbie in mathematical statistics and haven't learnt any group theory before. My lecture notes are too brief. How can the Borel subsets on $\mathbb R$ satisfy A.2 and A.3 of a $\sigma$-algebra ? </p>
<p>A.2 is closure under complement. A.3 is under countable unions.</p> | g19116 | [
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<p>I am slightly confused on a paper I am reading. They have a table of calculated Pearson coefficients as shown here:</p>
<p>$$
\begin{array}
. & I & II & III\\
A + B & 0.8 & 0.65 & 0.90\\
A + C & 0.73 & 0.46 & 0.83\\
B + C & 0.61 & 0.76 & 0.68\\
\end{array}
$$</p>
<p... | g62152 | [
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<p>Am currently using Naive Bayes for a multi labelled text document classification problem.</p>
<p>But I would like to know the differences (advantages and disadvantages) of using SkiLearn Naive Bayes or NLTK?</p>
<p>SkiLearn seems to have flexibility in parameter setting more than NLTK, but I'm think my thoughts on... | g62153 | [
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<p>I am studying the factors influencing the annual salary for employees at a undisclosed bank. The regression model that I have decided to employ is as follows:</p>
<p>\begin{equation}
Y_{k}=\beta_{1}+\beta_{2}E_{k}+\beta_{3}D_{gk}+\beta_{4}D_{mk}+\beta_{5}D_{2k}+\beta_{6}D_{3k}+\varepsilon_{k}
\end{equation}
where $... | g62154 | [
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<p>I need help in this area for my thesis. I have 2 time lines in my research in which different variables are measured. The only variable that is the same for both timelines is on stress. It was suggested to me that I can use multiple regression on a variable from time 1 and another variable in time 2 (as IVs) and ... | g586 | [
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<p>I am trying to understand how, using only the standard deviation and mean, you are able to determine the first and third quartiles on a normal distribution.</p>
<p>I get that the area under the curve equals one; I understand that Q1 accounts for 25% of the area, and Q3 75%; but I do not understand how to leverage t... | g49164 | [
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<p>I have a biological problem which involves using a 1-sided two-sample t-test. To simplify the problem, let’s assume an experiment comparing quantities in a control (C) and a treatment (T) group, each having 3 replicates, called C1, C2, C3, T1, T2, T3. Here, <strong>C1 and T1 are samples from the same subject, C2 and... | g19117 | [
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<p>I am working with presence/absence data that contains lots of zeros. What is the best method to model this. The only suggestions I can find for zero inflated data refer to count data not binomial/proportion data.</p> | g62155 | [
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<p>Given a probability density function (pdf),</p>
<p>$$P(x) = \frac{f(x)}{\Sigma_x f(x)}.$$</p>
<p>Is this still a valid pdf if the normalizing constant in the denominator, $\Sigma_x f(x) = \infty$?</p> | g62156 | [
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<p>The Area Under ROC curve (AUROC) is a quantity used to quantify performance of classifiers. I am currently interested in the most basic drawbacks of using AUROC as unique performance measure. </p>
<p>I got a negative feedback with AUROC in some recent analysis as I met a classification problem performed through a ... | g62157 | [
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<p>I am comparing two different cache hit algorithms using four different training and testing sets. The training sets are related: 1 is a subset of 2 is a subset of 3 is a subset of 4. The same goes for the test sets. The result is two different matrices with cache hit ratios between 0 and 1, where higher values are b... | g62158 | [
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<p>I'm analysing benchmark data for some of my R functions, and I'm trying to compute a statistic describing how many times faster my function - group_one - is than a control function - group_two - as a multiplier (group_one is $\alpha$ times faster than group_two).</p>
<p>The data are assumed to be normally distribu... | g19119 | [
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... |
<p>My aim is to find the best C for a linear SVM classification using libsvm, I have 120 instances in total and 2 classes which I want to classify.</p>
<p>I have question regarding partitioning a the dataset into these parts: 1) training for optimisation during parameter C search 2) training for model construction 3) ... | g19120 | [
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<p>I have done an experiment with 7 treatment conditions designed to reduce alcohol intake, and a control condition. The dependent variable is alcohol intake after treatment, and I have run an ANCOVA with baseline alcohol intake as a covariate.</p>
<p>I found no effect from the omnibus ANCOVA F-test, but wanted to inv... | g62159 | [
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0.03611817583441734,
0.07... |
<p>Is it possible to derive a formula for variance of powers of a random variable in terms of expected value and variance of X?
$$\operatorname{var}(X^n)= \,?$$
and
$$E(X^n)=\,?$$</p> | g62160 | [
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<p>I used 5-point Likert-type scales as a dependent variables (1 strongly agree, 2 agree, 3 neutral, 4 disagree, 5 strongly disagree), but, as you are aware, using binary logistic regression requires me to create a binary variable from these 5-level responses. So, strongly agree and agree would become category 1, and ... | g62161 | [
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<p>I have a extremely simple data set which consists of one independent variable (five sampling sites as factors) and the outcome variable which is disease status (positive/negative) in crabs from each site. These sites are located at varying distances from a sewage outfall point. My hypotheses are that 1) prevelence i... | g62162 | [
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<p>I've previously read about a theory that I remember (correctly or not) being called the "Winning Lottery Theory" which is essentially the following:</p>
<blockquote>
<p>An individual hears about disproportionately more occurrences of other
individuals entering a lottery and winning, than they do of others
ent... | g62163 | [
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<p>If x$_{1}$, x$_{2}$,...,x$_{n}$ ~ N($\theta$, $\sigma$$^{2}$), based on the fact that Y$_{1}$ = $\sum$(x$_{i}$) and Y$_{2}$ =$\sum$(x$_{i}$)$^{2}$ are complete and sufficient statistics, it can be shown that (not sure how)</p>
<p>MVUE of $\sigma$$^{2}$ = $\sum$(x$_{i}$- $\bar x$ )$^{2}$ / (n-1)</p>
<p>If I need t... | g19128 | [
0.0002062753919744864,
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... |
<p>Trying to understand a discussion of a 5-fold cross-validation process to validate a predictive model and its results, there is a particular phrase which has me stumped, i.e.: </p>
<blockquote>
<p>The predictions of the algorithm are significantly enriched with the
left-out test data.</p>
</blockquote>
<p><str... | g62164 | [
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0.0447077602148056,
-0.002471572486... |
<p>I implemented a rather simple MLP NN as a part of my project. I'm just testing it on a sinusoid right now and I expect this network's output to follow the sinusoid without issues. </p>
<p>Some network details:
32 input nodes
10 hidden nodes
I use tanh activation functions in both layers</p>
<p>I trained it using b... | g62165 | [
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0.0403... |
<p>Weighted least squares (WLS) and robust standard errors are sometimes presented as alternative approaches for obtaining reliable standard errors of estimates of regression coefficients in the presence of heteroscedasticity. However, I notice that my software (gretl) offers robust standard errors as an option when us... | g62166 | [
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... |
<p>An urn contains N-1 red and 1 green ball. Each ball has an associated weight. If each ball is drawn (without replacement) with a probability proportional to how much its weight contributes to the urn, what is the expected number of attempts required to get the green ball?</p>
<p>Example: 2 red balls of weight 0.3 a... | g62167 | [
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<p>I have some question which occupies myself for a while.</p>
<p>The entropy test is often used to identify encrypted data. The entropy reaches its maximum when the bytes of the analyzed data are distributed uniformely. The entropy test identifies encrypted data, because this data has a uniform distribution - like co... | g62168 | [
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-... |
<p>I have a problem with a 3 way ANOVA with repeated measures.
The design is the following: "localization" is the dependent variable, than I have the following within subjects factors "material" (4 levels), "diffusion technique" (6 levels) and "typology" (2 levels).</p>
<p>This is the formula I used: </p>
<pre><code>... | g62169 | [
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0.02818012796342373,
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0.0475069060921669,
0.056061021983623505,
0.00... |
<p>I used matlab corr() function to identify correlation of 236 samples. Pearson correlation is selected, and the output return r and p-value. Two sets of samples returned different r & p-value. May I know how to interpret the significance of correlation with the below results?</p>
<p>(a) The data has strong negat... | g49173 | [
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0.031177857890725136,
... |
<p>I am confused with the answers to the questions below
Assume that we have a dataset D with 100 examples, 50 of which belong to the class ’good’
and 50 belong to the class ‘poor’. Assume further that we have a very naïve learning algorithm
(L) that produces a model that simply predicts the majority class of the trai... | g19131 | [
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0.010392311029136181,
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0.02217281050980091,
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0.024117... |
<p>I have never had problems with R crashing before.</p>
<p>I am using the <code>mice</code> package (mice 2.13) to perform multiple imputations. The code works fine on some subsets of the data, but when I run it on other subsets, R crashes (not immediately - after some time). From the output in R just before it crash... | g49176 | [
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0.035738080739974976,
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0... |
<p>In general, how many points are needed to estimate a p-dimensional covariance matrix? Does it depend on how the data are spread out across the different dimensions? Does it depend on the true distribution of the data? Thank you!</p> | g12455 | [
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0.0128... |
<p>Edit: I updated the question to hopefully make it more easy to understand. I think it was overly complex.</p>
<p>I’m having a problem applying hidden Markov models to a game I’m building to learn about programming. </p>
<p>I have a game that tries to intelligently estimate what’s currently in your shopping basket... | g49532 | [
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0.016827763989567757,
0.04233383759856224,
0.0... |
<p>I am trying to extract variance components for selection and chance in a bifactorial design with <strong>Generation as a fixed factor</strong> and <strong>Replicate as a random term,</strong> for early fecundity. </p>
<p>Since I am using the individual level (because I want to make confidence intervals for Chance),... | g62170 | [
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0.012515561655163765,
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0.02882056124508381,
0.002051243092864752,
0.019... |
<p>I'm modelling an event with two outcomes, a and b. I have created a model which estimates the probability that either a or b will happen (i.e. the model will calculate that a will happen with 40% chance and b will happen with 60% chance).</p>
<p>I have a large record of outcomes of trials with the estimates from th... | g49179 | [
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-0.0... |
<p>An addition to the common confusion about normality testing in inferential statistics for general linear models:</p>
<p>I understand the assumption of normality refers to the residuals in ANOVA and regression models, but what about t-tests?</p>
<p>Calculation of the t-statistic uses standard deviation as a measure... | g49677 | [
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... |
<p>I know this is primarily a statistics site, so if I am off-topic, please redirect me.</p>
<p>I have a system with pumps that sometimes break and need to be replaced. I would like to be able to predict the failures, and thereby give early warning to the people replacing the pumps. I have historical data for the pump... | g62171 | [
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0.04876153916120529,
0.03584616258740425,
0.029638629406690598,
0.0... |
<p>I am trying to do a regression on heteroscedastic data where I'm trying to <em>predict</em> the error variances as well as the mean values in terms of a linear model. Something like this:</p>
<p>$$\begin{align}\\
y\left(x,t\right) &= \bar{y}\left(x,t\right)+\xi\left(x,t\right),\\
\xi\left(x,t\right) &\sim N... | g14673 | [
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0.01211677398532629,
0.026441805064678192,
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... |
<p>I have run a mixed model with one random effect, one fixed effect and a second order covariate effect. The random effect models the individual experimental units in my study. The LSMeans calculated for each experimental unit from the full model are quite different from the effects calculated running an individual mo... | g19143 | [
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0.030811108648777008,
0.007997117005288601,
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0.0437... |
<p>I am working on a project where I have to separate base and promotional volume from the sales data. I have sales data for the last 4 years at week level. How can I separate base and promotional volume from only this much data?</p>
<p>Is it possible to do by regression or any time series approach?
I'd appreciate any... | g19144 | [
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0.027686813846230507,
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<p>I have the mean (u) and the standard deviation (sd) of a continuous distribution (X). How do I solve for the mean (u_log) and standard deviation (sd_log) of the log of that continuous distribution (log(X))?</p>
<p>I am looking to draw random numbers from a log-normal distribution. The problem is, most statistical p... | g19147 | [
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... |
<p>I am doing a regression analysis with multiple variables and comparing it to a one-variable null hypothesis. The goal is to see which model provides a better explanation. The topic is information diffusion, hence the names DIFfusion, INDustry, etc. Also I must say that DIF is many times zero (has a long tail) and al... | g62172 | [
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<p>I'm looking for a paper that could help in giving a guideline on how to choose the hyperparameters of a deep architecture, like stacked auto-encoders or deep believe networks. There are a lot of hyperparameters and I'm very confused on how to choose them. Also using cross-validation is not an option since training r... | g62173 | [
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0.03730873391032219,
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0.020953809842467308,
0.01476674061268568,
0.01495... |
<p>What effect does data averaging have on the variogram? To be specific, please see a simple example:</p>
<pre><code>#Simulate a pure random walk data set, call this *PROCESS A*
n <- 1000 #number of data points
t <- 1:n #time
y <- cumsum(rnorm(n)) #data points
# Averaging at every 2 lags, call this *PROCES... | g62174 | [
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0.... |
<p>Here the basics:
Group 1 is the control group, they are given a specific website to use.
Group 2 is the experimental group, they are given a similar website, with adjusted hypertext properties. </p>
<p>After they complete the required actions, they are asked to complete a survey, (Likert Scale) which attempts to ... | g62175 | [
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0.024118905887007713,
0.0135266724973917,
0.0... |
<p>I'm new in the Data Mining World. I have a Dataset of 19 variables(some of them categorical). It is about execution time of different aplicattions. I have something like this) but with thousands of rows.</p>
<pre><code> app process subprocess ex_time place start_date start_time session
1 A A.a A.1 ... | g19148 | [
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0.03988293185830116,
0.07486123591661453,
0.000238... |
<p>Many times in statistics we are using a statistic in different ways. I think Intraclass correlation coefficient is one of them...</p>
<p>Intraclass Correlation Coefficient can be a
A) measure of inter-rater reliability, but it can also be used as
B) measure of dependency between scores (preliminary test of a multi... | g62176 | [
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0.04826240986585617,
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0.023... |
<p>I have several groups of sensor, each group send the data with different probability.</p>
<p>I want to classify these groups into 3 categories ( first category has no data to send , the second category has one sensor to send and the third category has more than one sensor sending data ) how can I write the probabil... | g19149 | [
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0.0022988610435277224,
0.0026653683744370937,
0.08677878230810165,... |
<p>Hi I have a set of data(message with different size) in excel like (over 5000 entries):</p>
<pre><code>message Name MessageSize
message1 0.5M
message2 10.2M
message3 2.1M
...
message n-1 40.52M
message n 12.12M
</cod... | g676 | [
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<p><br/>
The conditional quantile regression estimator by Koenker and Basset (1978) for the $\tau^{th}$ quantile is defined as
$$\widehat{\beta}_{QR} = \min_{b} \sum^{n}_{i=1} \rho_\tau (y_i - X'_i b_\tau)$$
where $\rho_\tau = u_i\cdot (\tau - 1(u_i<0))$ is a re-weighting function (called "check"-function) of the re... | g19152 | [
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<p>Is recasting a multivariate linear regression model as a multiple linear regression entirely equivalent? I'm not referring to simply running $t$ separate regressions. </p>
<p>I have read this in a few places (Bayesian Data Analysis -- Gelman et al., and Multivariate Old School -- Marden) that a multivariate linear... | g62177 | [
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<p>I have 2 factors, one (Page type) of 2 levels and the other (Intensity) of 4 levels. I did a 2x4 Full Factorial Design with 10 replications, so I did 80 experiments. Then I wanted to do a two-way ANOVA on these data. Correct me if I'm wrong, but what I have to check is if the residuals are indipendent, homoschedasti... | g62178 | [
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<p>I have a bit a naive question about Poisson process.</p>
<p>Suppose I have a station that receives a number of packets $n(i)$ each time slot $i$. If the number of received messages is less than $M$ then the $n(i)$ packages will all be sent. </p>
<p>If $n(i) > M$ then $n(i)-M$ packets will be lost and $M$ packet... | g19153 | [
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<p>I am having trouble to understand where and how many times to use set.seed().</p>
<p>I am performing a leave-one out crossvalidation on a set with 120 classified variables to predict another 300 of unknown class. Should I set the seed at the beginning of the code or at the beginning of each iteration of the leave-o... | g62179 | [
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<p>if I have A and B with the following known variables:
with $E[A]$, $E[B]$ , $\sigma_{A}$ , $\sigma_B$
and correlation coefficient: $\rho_{AB}$ (assign numbers if you like)</p>
<p>Say: $C=0.6A+0.4B$
Then how can I find $\rho_{AC}$?</p>
<p>I know how to find: $E[C]$ ,$Var[C]$, but not how to find $\rho_{AC}$...
I h... | g62180 | [
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<p>I am running a generalized linear model on a dataset with 19 individuals and have 4 variables of interest. There are furthermore a number of interactions that might be interesting to look at. I was wondering if there is a general rule of thumb (with reference please) about the nr of terms you can use in a model base... | g43331 | [
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<p>I am interested in utilizing Maximum Difference Scaling (Max Diff) for a survey, but apart from the Sawtooth software, I was not able to find a good answer on how to best analyze Max Diff.
What is the best way to represent the result in my dataset, and which steps are used to analyze the data? I would prefer to use ... | g48751 | [
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<p>My name is Abhi & I am trying to better understand logistic regression by solving a few practice problem. I am using R and RStudio as the development environment</p>
<p><strong><em>Problem Statement</em></strong>
<br>
Given the age, sex and class(first,second,third) for each passenger can you predict if he surv... | g62181 | [
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<pre><code> names(mydat)[c(name)]<-c("newname")
</code></pre>
<p>From this, I know that the column/variable name "name" of the data frame mydat is replaced with "newname".</p>
<p>My question is if, I want to do this by a loop so that I will have some thing like:</p>
<p>newname1 newname2 newname3 newname4 and so ... | g62182 | [
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<p>From Bickel and Doksum's Mathematical Statistics</p>
<p><img src="http://i.stack.imgur.com/pdDbe.png" alt="enter image description here"></p>
<p><img src="http://i.stack.imgur.com/wCZNu.png" alt="enter image description here"></p>
<p>I was wondering what "$\Theta_0$ is of smaller dimension than $\Theta = \Theta_0... | g62183 | [
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<p>We know the expected value of $1 \over X$, where $X$ is a normal random variable, does not exist. But suppose we condition on an interval not containing zero. For example, if $ \mu_X = 10$ and $\sigma_X = 1$, what is </p>
<p>$E [{1 \over X} | ( 9<X<10 )] $ ? </p>
<p>I know numerical integration or an appr... | g37058 | [
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<p>In G power 3, ANOVA repeated measures within-between interaction: Only the total sample size is reported assuming equal sample size for the two groups. </p>
<p>My questions are:</p>
<ol>
<li>How would it work if the sample sizes are slightly different, for example: N1/ N2 = 1.16. </li>
<li>I have to input correlat... | g37059 | [
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<p>I have a strategy that has a Sharpe ratio of 1.6 when back tested over the past 10 years. When I run this same strategy on re-sampled data, the performance of the strategy goes down to 1.32.</p>
<p>Should I derive the expected return from the performance of the bootstrap results? Does the difference in performanc... | g62184 | [
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<p>I am having a big trouble to determine the kernel i should use in a non linear SVM without testing before, I want to know if there is any other ways to determine the best kernel without tests ? Is it linked to the data we are working on ? </p> | g20184 | [
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<p>I did a number of machine learning experiments to predict a binary classification. I measured precision, recall and accuracy.</p>
<p>I noticed that my precision is generally quite high, and recall and accuracy are always the same numbers.</p>
<p>I used the following definitions:</p>
<p>$\text{Precision} = \frac{T... | g62185 | [
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<p>I am discussing how growth of a business changes over a time period with a colleague. The issue is, that I want to extrapolate the impact of business investment beyond maintenance. </p>
<p>The example is a hotel chain with n hotels in year one. In year two have $n + x - y$ hotels, where $x$ are new openings and $y$... | g62186 | [
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<p>I'm analyzing a website, we have three variables Pageviews, Minutes spent on site and Entrances and want to produce a score that gives equal weight to each of them.</p>
<p>At first I was simply going to multiply them but this would give different weight to each:</p>
<pre><code>PageViews * Minutes * Entrances = Sco... | g62187 | [
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<p>Any hints on how to solve this problem?</p>
<blockquote>
<p>A sample of 400 items is taken from a normal population whose mean
as well as variance is 4. If the sample mean is 4.5, can the sample
be regarded as a truly random sample?</p>
</blockquote> | g5342 | [
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<p>I am a SAS programmer and am trying to help out a mate doing a project for work.
He has tested 7 different treatments (growth cultures) across 31 days, I have a value from each treatment for each of the 31 days. The days go from Day 0 to Day 31, and the nature of the testing is that the values at day one are 0 and i... | g62188 | [
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<p>I am reading and trying to understand the paper "Gaussian Processes for Signal Strength-Based Location Estimation" by Ferris et al. (A copy of the paper may be accessed <a href="https://www.cs.washington.edu/ai/Mobile_Robotics/projects/activity-recognition/postscripts/gp-localization-rss-06.pdf" rel="nofollow">here<... | g62189 | [
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<p>My basic question is: What is an adaptive copula?</p>
<p>I have slides from a presentation (unfortunately, I cannot ask the author of the slides) about adaptive copulae and I am not getting, what this means resp. what this is good for?</p>
<p>Here are the slides:
<img src="http://i.stack.imgur.com/0F76A.png" alt="... | g62190 | [
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<p>I'm looking for books on genetics or biology in general, at an introductory level, ideally where topics are tackled from a statistical point of view. I've been reading "Genes population and languages" by Luca Cavalli-Sforza these last few days and I'm enjoying it a lot, something similar would be perfect.</p>
<p>To... | g37097 | [
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<p>I am using a chi-sq test between two proportions (<a href="http://statistic-on-air.blogspot.com/2009/07/comparison-of-two-proportions.html" rel="nofollow">http://statistic-on-air.blogspot.com/2009/07/comparison-of-two-proportions.html</a>). I am using this over the z-test for proportions because I do not think my da... | g19167 | [
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0.024188634008169174,
... |
<p><img src="http://i.stack.imgur.com/iRvX5.png" alt="enter image description here"></p>
<p>Above is output from SAS. </p>
<p>What would be the corresponding ARIMAX equation? I would appreciate if someone could help me write the mathematical equation, preferably in the following form:
$$
Y(t)= ay(t-1) + by(t-2) + \l... | g62191 | [
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0.... |
<p>I do not come from a mathematical background, and hope you can answer this (probably very basic?) question.</p>
<p>I got a game group with friends where we play board games, normally 3-6 players each night. I have created an application which keeps track of game history, and keeps track of a <a href="http://en.wiki... | g62192 | [
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<p>I am using lsmeans to run post-hoc analysis for contrasts of linear mixed model, and here is the output:</p>
<pre><code>$contrasts
contrast estimate SE df t.ratio p.value
aL2_like - english 450.7397 252.6889 75.99 1.784 0.1819
aL2_like - thai 224.6113 127.8683 59.66 1.757 0.1931
e... | g62193 | [
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0.043... |
<p>I am using AdaBoost Classifier to predict values I have. How can evaluate the accuracy of prediction model (I'd like to see how the accuracy of predicted values).</p>
<p>You can check an example here: <a href="http://scikit-learn.org/stable/modules/ensemble.html#usage" rel="nofollow">http://scikit-learn.org/stable/... | g62194 | [
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<p>I've implemented a discrete HMM according to this tutorial
<a href="http://cs229.stanford.edu/section/cs229-hmm.pdf" rel="nofollow">http://cs229.stanford.edu/section/cs229-hmm.pdf</a></p>
<p>This tutorial and others always speak of training a HMM given an observation sequence. </p>
<p>What happens when I have mult... | g19169 | [
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0.03... |
<p>I measured 2 continous dependent variables (V1 and V2) on 10 occasions (10 replicates) for each of 4 groups. </p>
<p>I aim to cluster my groups. i.e. I dont want to cluster replicates, since this could mix groups inside a cluster. I see two options:</p>
<ol>
<li>hierarchical clustering on group-average (V1mean and... | g62195 | [
0.019066907465457916,
-0.03420634567737579,
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-0.010462475009262562,
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-0.00721840001642704,
0.014624389819800854,
0.04449376463890076,
0.024255795404314995,
... |
<p>Bus tickets in certain city contains four numbers u,v,w,x. Each of these numbers is equally likely to be any of the 10 digits 0,1,2....,9 and four numbers are chosen independently. A bus rider is said to be lucky if u+v=w+x. What proportion of riders are lucky?</p> | g62196 | [
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0.02716202288866043,
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-0.028908612206578255,
-0.0017753014108166099,
-0.014841423369944096,
0... |
<p>This an exercise given in <strong>Probability Theory: The Logic of Science</strong> by Edwin Jaynes, 2003. There is a partial solution <a href="http://ksvanhorn.com/bayes/Papers/sanders.pdf">here</a>. I have worked out a more general partial solution, and was wondering if anyone else has solved it. I will wait a ... | g62197 | [
0.024025805294513702,
0.006975903175771236,
-0.005503644701093435,
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0.0018139863386750221,
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0.016095692291855812,
0.01946316659450531,
-0.0046769441105425... |
<p>I have a data sample (in this case an EEG data sample, but my question refers to any type of data samples of prior unknown distributions).</p>
<p>I would like to do a nonparametric estimate of the expected value for my sample. I did some research, from what I understood I can do this using bootstrap sampling. I fou... | g19170 | [
-0.006898495368659496,
0.017012953758239746,
0.011473769322037697,
-0.05662382394075394,
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0.011799925938248634,
0.01962622068822384,
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-0.026169614866375923,
0.028944171965122223,
-0.008031523786485195,
0.026866231113672256,
0... |
<p>I am working on the project that requires data mining. I have been asked to use R. I have a dataset with all categorical variables and would like to form clusters on that. I am unable to figure out how to do so in R. </p>
<p>Here is what I have done: I have converted all the variables to "factor" data type in R. Bu... | g62198 | [
0.002332460368052125,
-0.013695799745619297,
-0.013376194052398205,
-0.021689578890800476,
-0.0043352581560611725,
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0.0013391623506322503,
-0.002221624832600355,
-0.034972578287124634,
0.017035290598869324,
0.0570032000541687... |
<p>I met a problem related to conditional probability from the article "Bayesian Networks without Tears"(<a href="http://www.aaai.org/ojs/index.php/aimagazine/article/view/918/836" rel="nofollow">download</a>) on page 3. </p>
<p>According to the Figure 2, the author says
$$P(fo=yes|lo=true, hb=false)=0.5$$</p>
<p>Wh... | g62199 | [
0.037583786994218826,
0.02874242141842842,
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0.01745838113129139,
-... |
<p>The below sample graph was created using R, for an example I came across while reading (on Distribution of time until customer x arrives):</p>
<pre><code>t <- seq(0,1,0.01)
ft <- 100*t*exp(-10*t)
plot(t,ft,type="l", xlab="T", ylab="f(t)")
title(main=expression(paste("Probability density function of ", Gamma(2... | g49345 | [
0.0160130113363266,
-0.014640729874372482,
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-0.0038049921859055758,
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0.03651551157236099,
0.03707972168922424,
0.007533402182161808,
0.0673566460609436,
-0.0467... |
<p>I would like to specify a Toeplitz variance matrix for the random effects of my <code>nlme</code> model in <code>R</code>. Is it possible ? More precisely, my model looks like</p>
<pre><code>lme(y ~ dose, data = dat, random = list(Lot = pdSymm(~ 0+dose )))
</code></pre>
<p>but I want a Toeplitz matrix instead of t... | g62200 | [
-0.061348818242549896,
-0.04450333118438721,
0.014085378497838974,
-0.06362520158290863,
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-0.08232072740793228,
0.0011945640435442328,
0.014130986295640469,
0.039261557161808014... |
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