question stringlengths 37 38.8k | group_id stringlengths 2 6 | sentence_embeddings listlengths 768 768 |
|---|---|---|
<p>Wackerly et al's text <a href="http://books.google.com/books?id=ZvPKTemPsY4C&lpg=PA318&vq=theorem%206.1&pg=PA318#v=snippet&q=theorem%206.1&f=false" rel="nofollow">states</a> this theorem "Let $m_x(t)$ and $m_y(t)$ denote the moment-generating functions of random variables X and Y, respectively. I... | g67102 | [
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<p>I am considering using signal processing techniques to find the minimum on a noisy 1D response line. More specifically I have a simulation that requires one parameter, but also includes randomness, and I want to adjust the parameter to fit some data. By fixing the parameter, I can have many different answers by runn... | g67103 | [
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<p>Q: Does there exist experimental evidence supporting Tufte-style, minimalist, data-speak visualizations over the chart-junked visualizations of, say, <a href="http://www.nigelholmes.com/home.htm">Nigel Holmes</a>? </p>
<p>I asked how to add chart-junk to R plots <a href="http://stackoverflow.com/questions/8109610/m... | g67104 | [
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<p>I was just wondering if it is possible to pool the data into groups before doing prcomp() in R? I have i.e. 100 individuals (rows) and 50 measurements(cols) with individuals being grouped in separate populations (20 in the first, 30 in the second, 15 in the third...etc). Now PCA can give scores of individuals or mea... | g26485 | [
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<p>Given the random variable</p>
<p>$$Y = \max(X_1, X_2, \ldots, X_n)$$</p>
<p>where $X_i$ are IID uniform variables, how do I calculate the PDF of $Y$?</p> | g67105 | [
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<p>I don't have much experience with statistics (my education included 8 credits of pure statistics, another 8 of related subjects). I mostly learned about distributions and significance tests for distribution parameters, and a bit about linear regression. I also had some factor and component analysis, but have complet... | g67106 | [
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<p>We ran a CHAID decision tree model using the set up and process described in my related question <a href="http://stats.stackexchange.com/questions/33448/deployment-process-for-classification-models-i-e-decision-trees">here</a>. We used the propensity scores to come up with a prediction. We measured the prediction at... | g67107 | [
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<p>I'm having tremendous difficulty evaluating $_2F_1(a,b;c;z)$ with the <code>hypergeo</code> package in R. In my case, values of $a$, $b$, $c$ are always positive real numbers. Even so, the hypergeometric function is incredibly sensitive to their values. I am not looking for extreme precision; I can use Excel to get ... | g26488 | [
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<p>I would be very grateful if someone could explain to me how hidden markov models are used to generate a sequence alignment. I was trying to read on it, however ended up in attaining basic concepts and I'm interested in the mechanism that takes place in between the two points: I input 2 or more sequences (first) and ... | g26489 | [
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<p>I was wondering if anybody could give a concise rundown as to the definitions and uses of p-values, significance level and type I error.</p>
<p>I understand that p-values are defined as "the probability of obtaining a test statistic at least as extreme as the one we actually observed", while a significance level is... | g67108 | [
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<p>I am using <code>RPART</code> for Classification and regression tree. I was tempted to use <code>bagging</code> function in <code>ipred</code> package in R, after reading about it. Now I am puzzled how to get the final set of rules similar to the ones I was getting in the output of <code>rpart</code>? </p>
<pre><co... | g67109 | [
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<p>I just noticed that integrating a univariate random variable's quantile function (inverse cdf) from p=0 to p=1 produces the variable's mean. I haven't heard of this relationship before now, so I'm wondering: Is this always the case? If so, is this relationship widely known?</p>
<p>Here is an example in python:</p>
... | g67110 | [
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<p>There are several posts I have read that addresses hourly electric load forecasts, but none address the question I have now.
If I am building a Dynamic sort of regression model that attempts to forecast hourly demand for a product, based upon hourly advertising impressions or GRP's, how do I model lead/lag effects ... | g67111 | [
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<p>I have started research in Electronic Engineering, where PDF & CDF take a core part in most of the applications. I have studied books on probability where they have discussed the PDF & CDF formulas and basic theory. But my objective is different, like thinking about their applications: e.g. If I take any gra... | g25962 | [
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<p>Suppose we are performing ordinal regression using a probit link function. The data are doses (log transformed) and responses. The responses are ordinal and can be from 0 to 4. Suppose that some of the responses are not seen in the data (e.g. 1 and 3). The variance covariance matrix from R looks like:</p>
<pre><cod... | g26494 | [
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<p>The autocovariance is defined as</p>
<p>$$\gamma(t,s) = Cov(X_{t}, X_{s})=E[(X_{t}-\mu_{t})(X_{s}-\mu_{s})]$$</p>
<p>When we have a stationary process the only thing that matters is the lag between the variables:</p>
<p>$$\gamma_{k} = Cov(X_{t}, X_{t-k})=E[(X_{t}-\mu)(X_{t-k}-\mu)]$$</p>
<p>However, the expectat... | g67112 | [
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<p>I have two groups of data, one consisting of 9 subjects and another consisting of 5 subjects. In the 9 subjects group, 5 of those could be paired with the 5 subjects from the other group. I could run a paired samples t-test and cut out the data for the 4 subjects that cannot be paired or I could run an independent s... | g67113 | [
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<p>Is there available software (or even just relevant papers) that can perform multiclass learning on datasets of 200m+ samples with 50+ classes and 1000+ features?</p>
<p>What are the limits on dataset sizes for neural networks? Decision tree ensembles? SVM?</p>
<p>As an example: Microsoft has developed code that ca... | g26495 | [
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<p>I have daily rainfall data for a given site going back about 30 years.</p>
<p>I have a building with an average daily demand for water of $L$ litres and a catchment of $A$ m$^2$ with a runoff coefficient of $c$.</p>
<p>How can I construct a model so that I can determine for a tank size T litres, The mean and varia... | g67114 | [
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<blockquote>
<p><strong>Possible Duplicate:</strong><br>
<a href="http://stats.stackexchange.com/questions/15597/heteroscedastic-test-does-not-solve-the-problem">Heteroscedastic test does not solve the problem</a> </p>
</blockquote>
<p>I have two list with around 700 daily prices(each) I would use a garch (1,1)... | g49767 | [
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<p>Hyndman's great explanation of proper time series CV is at the bottom of the page in the following link: <a href="http://robjhyndman.com/hyndsight/crossvalidation/" rel="nofollow">http://robjhyndman.com/hyndsight/crossvalidation/</a></p>
<p>Leave-One-Out illustration in the following link: <a href="http://i.imgur.c... | g67115 | [
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<p>I am trying to update my lm() based model to get correct standard errors and tests. I am really confused which VC matrix to use. The <code>sandwich</code> package offers <code>vcovHC</code> , <code>vcovHAC</code> and <code>NeweyWest</code>. While the former only accounts for heteroskedasticity the latter two account... | g67116 | [
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<p>A king has rounded up 1000 people suspected of counterfeiting coins, which look and feel the same as the official coin. However, only the official coin is truly fair (Pr(heads)=0.5), while all fake coins produce strongly skewed coin flip results (biased towards heads or tails).</p>
<p>The king decides to identify t... | g67117 | [
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<p>I have a lottery style dataset we produce internally (example below). I am trying to figure out which numbers appear most frequently together. Example questions:
What are the top 10 pair of numbers that appear most frequently together?
What are the top 10 three numbers that appear most frequently together?</p>
<p>W... | g67118 | [
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<p>I am involved with a survey where 3 different patient measurement scoring systems were used. They all are used as surrogate outcome measured for patient self- management.
All scoring systems are on a different scale - that is one ranges from 0-100, another 1-8 and other 1-10.
The research wants to z-score each measu... | g67119 | [
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<p>As I understood from my experimentation on some multivariate data-sets, anomaly detection (AD) heavily depends on the underlying distribution of data. Like, for ex., you can devise a method to detect anomalies supposing a Gaussian distribution for your data, and then end up with a failure if it is actually a power-l... | g67120 | [
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<p>Original simple question:</p>
<p>"Given a fair coin that has been tossed 100 times, each time landing heads, would it be more likely that that the next coin flip be tails or heads"</p>
<p>The proportion of head to tails is 1 to 1 as number of trails approach infinity (this is a fact correct?). Therefore, if this m... | g46999 | [
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<p>Which (if any) <a href="http://en.wikipedia.org/wiki/Heavy-tailed_distribution" rel="nofollow">heavy-tailed distributions</a> can we compute the maximum likelihood parameters of, given some data to fit the distribution to?</p> | g67121 | [
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<p>i am trying to model the following data in SAS using proc glimmix and i would like feedback if i have modelled my data correctly. </p>
<p>My data consist of individual chickens (ID) who are grouped by treatment in the enclosure they occupy (chickens receiving different treatments are kept in the same enclosure). I ... | g67122 | [
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<p>I'm struggling with this problem.</p>
<p>For the analysis of my test, I was instructed to use chi-square test for one group.
I use Statistica and everywhere I try to do this I need the expected values, which I don't have (or I don't know how to prepare it).
The analysis is crucial for my PhD. </p>
<p>In the te... | g67123 | [
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<p>When learning how to use a statistical model, I often create a simulation of the DGP, and run simulated data through the software to make sure I know what I'm looking at.</p>
<p>I've done this for Proc ARIMA in SAS, and for the most part the results are expected.</p>
<p>One thing I'm finding surprising is that if ... | g26504 | [
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0.01390733104199171,
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0.06239263340830803,
-0.0226... |
<p>I have a very simple logistic regression in which the binary variable Y is regressed on three continues variables, X1 and logX2 and X1*LogX2. X1 is a proportion (is between 0 and 1), logX2 is the natural logarithm of the continues variable X2 and X1*LogX2 is the interaction of these two variables. I have calculated ... | g67124 | [
0.04279273375868797,
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<p>Suppose you have an urn filled with money. You know there are $N$ total bills, and that each is either a \$1, \$10, or \$100. You draw $n$ bills without replacement from the urn, and wish to construct, say, a confidence lower bound for the total amount of money in the urn.</p>
<p>The obvious solution is if $n$ is s... | g26505 | [
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<p>I am trying to estimate the time it will take me to run a tuning grid on gbm (I am using the R Caret package but this is irrelevant as I am interested in the relative processing time).</p>
<p>I can see many parameters:</p>
<ul>
<li>number of rows and columns of the data set,</li>
<li>number of resampling (I am usi... | g26507 | [
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<p>How to create a feature vector from text with a deep learning aproach?. Im new at this topic, could anybody advice me where to start and how to aproach this task?.</p> | g67125 | [
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<p>I am looking for online resources or books explaining how to develop prognostic indexes-scores step by step. I am mainly wondering about model validation and transformation of regression coefficients into scoring systems.</p> | g47006 | [
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<p>Let $X_1, X_2, ... , X_n$ i.i.d random variables with probability density function $N(\theta, \theta^2)$. Show that</p>
<p>$$T(X) = \frac{X_{(1)}-X_{(n)}}{X_{(2)}-X_{(n)}}$$</p>
<p>is ancillary to $ \theta$.</p>
<p>My attempt: Since $\frac{X_i}{\theta} \sim N(1,1)$, which does not depends on theta, we have that i... | g67126 | [
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<p>Regarding multicollinearity, is it recommended to use ridge-regression if you have some covariates with VIF values around 10 in the OLS model? What would be the best VIF level to use to decide whether or not to do ridge-regression?</p> | g67127 | [
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<p>I would like to use <a href="http://en.wikipedia.org/wiki/Exponential_smoothing#Double_exponential_smoothing">double exponential smoothing</a> to predict prevalence rates of care dependency in Austrian federal states. </p>
<p>My data is very detailed, thus I would like to make use of that in order to refine my pred... | g67128 | [
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<p>My colleague and I do the exactly same thing with the exactly same data and get different results. He uses Stata, I use R. We both use 32-bit Windows machines.</p>
<p>Are there any possible explanations apart from human failure for this?</p>
<p>The concrete problem is calculating c-indices for Cox models. His are ... | g47009 | [
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<ol>
<li>Can someone help me to understand fixed/random effect models? You may either explain in your own way if you have digested these concepts or direct me to the resource (book, notes, website) with specific address (page number, chapter etc) so that I can learn them without any confusion. </li>
<li>Is this true: "... | g38085 | [
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<p>I'm working on a medical research project where we're looking at the changing resonances in femur bones during hip replacement operations. Some surgeons use the increasing pitch of the bone resonance to tell them when to stop hammering/reaming the shaft of the feamur. If they apply too much pressure when creating th... | g26512 | [
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<p>Could someone please explain what the difference is between the two, and perhaps avoid the worst statistical jargon?</p>
<p>I am currently using the <code>dlm</code> package to model dynamic regressions as can be seen on p.122-5 in <a href="http://rads.stackoverflow.com/amzn/click/0387772375" rel="nofollow">Dynamic... | g26513 | [
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<p>I'm having trouble understanding what a correct model for my data should be, and also if it would even be a good idea to make it a single model. </p>
<p>At the basis it is a rather simple regression model with two predictors. The predictors are 'perceived ease of use' (ease) and 'Perceived Usefulness' (useful), and... | g26514 | [
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<p>So I am using the R code behind Fig. 3.14 in <a href="http://rads.stackoverflow.com/amzn/click/0387772375" rel="nofollow">Dynamic Linear Models With R</a> (p. 124-5) to make a dynamic version of a simple pair trading model:</p>
<p>$$
Y = \alpha + \beta X.
$$</p>
<p>If I use log returns (<code>diff(log(P))</code... | g67129 | [
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<p>I would like to perform something like a linear regression on my distribution of data, but I'm interested in a trendline that estimates the <strong>minimum</strong>, <em>not mean</em>, value for each time bin. I'd like to do this in R.</p>
<p>The image below shows a scatterplot of the minimum value for each time bi... | g67130 | [
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<p>Self organizing maps are claimed to be able to visualize/cluster high-dimensional data in a smaller dimensional space. I have some difficulties in understanding this statement.</p>
<p>Consider a six-dimensional data set; the codebook vector/reference vector is also six-dimensional. According to the SOM algorithm,... | g49617 | [
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<p>I would like to fit a model of the form <code>weight ~ bs(height) + id</code>, where id is a factor (so I have several observations per every id). There are perhaps 100k values of <code>id</code>. Does anyone know the best way to go about fitting this? I have tried the mgcv package, but I do not think it was desi... | g67131 | [
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<p>Does anyone have experience or knows a good source where SVM are used to perform target motion analysis?</p>
<blockquote>
<p><a href="http://en.wikipedia.org/wiki/U.S._Carrier_Group_tactics" rel="nofollow">A general maneuver tactic against submarines is a zig-zag. A submarine usually relies on passive detection, ... | g47014 | [
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<p>I have a trial where the measurement is the deviation about a target value. </p>
<p>There are 8 subjects - 4 treatment, 4 control. Each subject has undertaken the trial 4 times. Thus, I have 32 values, nested within groups. Obviously this is a rather small number</p>
<p>Essentially, my treatment is effective if it... | g47015 | [
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<p>I am modeling a binary DV with a factor variable consisting of 8 clasess. I know I could just analyse the distribution of the DV across all factor classes but I will add more variables and wanted to start the predictive model with a regression approach.</p>
<p>The training set is :</p>
<pre><code>> head(learn_s... | g17321 | [
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0.02354222... |
<p>I am not sure if this is possible, but my question is - Is it possible to use different sets of independent variables in the same model for different values in a multinomial logistic regression model? </p>
<p>In other words, I have a set of variables, which are applicable to only one dependent value and not to othe... | g67132 | [
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<p>I am a programmer, not a statistician, so pardon my botched use of the terms. My basic problem is this: I am wanting to calculate $R^2$ between a known concentration (which can be any non-negative value) and a discrete measurement (where the values are all integers). There are 92 possible observations, and each o... | g26524 | [
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<p>What is the back-propagation algorithm and how does it work?</p> | g67133 | [
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0.008... |
<p>I have the following data: I have participants who answered on their favorite out of 6 positions of various information types on a display (e.g. 1 = bottom left, 2 = top left etc.).</p>
<p>I can now say for example the information “CPU status” was preferred to be shown on the top left by most of the participants, i... | g26525 | [
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... |
<p>As I understand UK Schools teach that the Standard Deviation is found using:</p>
<p><img src="http://upload.wikimedia.org/math/e/e/4/ee485814ab9e19908f2b39d5d70406d5.png" alt="alt text"></p>
<p>whereas US Schools teach:</p>
<p><img src="http://upload.wikimedia.org/math/8/3/a/83a7338b851dcaafaf5b64353af56596.png" ... | g67134 | [
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0.0... |
<p>Are there any objective methods of assessment or standardized tests available to measure the effectiveness of a software that does pattern recognition?</p> | g67135 | [
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<p>What do they mean when they say "random variable"? </p> | g67136 | [
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<p>What are the main differences between performing Principal Components Analysis on a correlation and covariance matrix? Do they give the same results?</p> | g49660 | [
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<p>On page 261 of <a href="http://books.google.nl/books/about/Applied_linear_regression_models.html?id=3_AlAQAAIAAJ&redir_esc=y" rel="nofollow">Kutner</a>, the author cautions readers about hidden extrapolations in linear regression. As shown in the figure, the allowed region for prediction is not a rectangle delim... | g67137 | [
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<p>The free energy is defined as such: </p>
<p>$F(v)=-ln(\sum_he^{-E(v,h)})$</p>
<p>What I don't understand is how to compute this $\sum_h$ ? If I know $E(v,h)$, how can I compute $F(v)$. </p>
<p>I have seen several definitions of $F(v)$ for a binary-binary RBM, but I have not been able to work it out from $E(v,h)$ ... | g67138 | [
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<p>I am running an A/B test, and the following are samples of how many questions a user has answered. I am trying to figure out which test is better (A or B), and how confident we are that it is better. For example, in Sample A, first user answered 4 questions, next two users answered 5 questions. </p>
<p>I know how... | g67139 | [
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0.025259656831622124,
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0.022... |
<p>I have very little stats training, so this may be a very obvious and boring question, in which case I apologise.</p>
<p>Given two real-valued continuous random variables A and B, and given prior probability distributions $f_A$ and $f_B$ for each, how do I perform a Bayesian update when given the extra evidence that... | g29544 | [
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<p>I would like to find if the particular two numbers in a vector belong to the same or different groups,</p>
<p>For instance, I have a set of vector data: $$d_1=\{100, 120, 104, 110, 20, 25, 30, 35\}$$ I want to know whether $100$ and $35$ belong to the same group or not.</p>
<p>By just looking at this, it is found ... | g67140 | [
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<p>Is the ar1 coefficient from an AR(1) model the "first order correlation of the noise" of a time series?</p>
<p>I'm using R's <code>aws</code> package and one of the arguments of the <code>aws</code> function allows you to "specify a first order correlation of the noise". Instinctively, I did</p>
<pre><code>arima (... | g49913 | [
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<p>I have been running a linear regression, and one of the variables was a discrete variable (3 categories), decoded into three binary variables.</p>
<p>I ran the regression in Stata. The first of those three variables was omitted, the other two were tested for significance (a ttest I assume); the resulting p-values w... | g67141 | [
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<p>If I want to compare the goodness-of-fit of two regression models, with and without intercept, is it valid to compare the squared correlation coefficient between the fitted values and the data? Since the squared correlation would get back the $R^2$ for the model with intercept, it seems to make sense to compute the ... | g26532 | [
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<p>I have a q and for with the answer, but cannot get the same. The q is based in table form with a list of major diseases around the world and the date collected for three years total deaths x1000. for each year. i.e: TUBERCULOSIS IN 1999 WAS 1669 DEATHS(x1000), In 2000 was 1660 (x1000) and in 2001 was 1644(x1000). </... | g67142 | [
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<p>I used <code>glmnet</code> to build a predictive model with ~200 predictors and 100 samples for a binomial regression/classification problem. This was my training data. I selected the best model (16 predictors) that gave me the maximum AUC. I have an independent test data set with only those variables (16 predictor... | g26533 | [
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<p>Let T be an efficient estimator for a parameter $\theta$. Let $g(\cdot)$ be a (real valued) non-linear function. Is $g(T)$ an UMVUE for $g(\theta)$?</p> | g49420 | [
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<p>I have a data frame with two categorical variables (representing different methods) that "classify" objects into three categories: <code>cat1</code>, <code>cat2</code>, <code>cat3</code>. The objects are classified somewhat differently by the two variables and I would like to perform a test described as "Measuring A... | g67143 | [
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<p>I'm planning an analysis that will require pooled logistic regression to analyze a longitudinal dataset with time-dependent explanatory variables (see <a href="http://www.ncbi.nlm.nih.gov/pubmed/2281238" rel="nofollow">here</a> - D'Agostino, et al. 1990). However, the standard analysis uses regularly spaced interval... | g26536 | [
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<p>We have a lot data generated from a genetic algorithm. We run this algorithm multiple times with different 'initial populations', meaning different items chosen for the initial group of items. We wish to show that the results from different runs are the same (statistically very similar) independent of the initial po... | g67144 | [
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<p>I already asked <a href="http://stats.stackexchange.com/questions/67017/results-of-bootstrap-reliable">a question about the interpretation of the results of the bootstrap algorithm in case of a normal mixture</a>. This time, I fit a hyperbolic distribution. According to this <a href="http://stats.stackexchange.com/q... | g67145 | [
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<p>I'm looking into calculating a Pseudo $R^2$ used McFadden's method for a zero-inflated negative binomial regression. I'm unclear how to go about evaluating $\hat L(M_{intercept})$ in R. Any suggestions for how this might be easily done?</p>
<p>R Code thus far: </p>
<pre><code>> require(pscl)
> require(MASS)
... | g26538 | [
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<p>To support an education project around neglected infectious diseases in Sub-Saharan Africa, I aim to estimate and report some very basic epidemiological models in R to build intuition and understanding with the students.</p>
<p>I have been searching for a little bit (to no avail) - does anyone know of basic R-based... | g67146 | [
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<p>I've spent the morning teaching myself about Bayes's theorem, because I assumed that it was required to help me solve my problem. However, the answer I've ended up with is the same as I would have got if I had used my naive approach prior to understanding Bayes's rule.</p>
<p>I'll explain my problem:</p>
<p>Suppos... | g47036 | [
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<p>I've found two definitions in the literature for the autocorrelation time of a weakly stationary time series:</p>
<p>$$
\tau_a = 1+2\sum_{k=1}^\infty \rho_k \quad \text{versus} \quad \tau_b = 1+2\sum_{k=1}^\infty \left|\rho_k\right|
$$</p>
<p>where $\rho_k = \frac{\text{Cov}[X_t,X_{t+h}]}{\text{Var}[X_t]}$ is the ... | g17328 | [
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<p>When reporting results of a bootstrapped independent samples t-test, can I just report the t statistic alongside the bootstrapped p value? Or do I also need to report confidence intervals? </p> | g67147 | [
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<p>I have a number of samples $X_1,\ldots,X_n $ from Gaussian distributions centered at $\mu_1,\ldots,\mu_n $ respectively.</p>
<p>I need to construct a confidence interval for the biggest difference between means $\max_{1\leq i<j\leq n}|\mu_i-\mu_j|.$</p>
<p>How can this be done? Probably that interval should be ... | g67148 | [
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<p>Some data are confidential such as patient data. Therefore sometimes companies does not want to give original patient data instead they first encrypt it(for instance with SHA1) and then give.</p>
<p>If we are given some encrypted data and run the following algorithms;</p>
<ul>
<li>ID3</li>
<li>CART</li>
</ul>
<p>... | g26539 | [
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<p>I am now working with the Gibbs sampling. One problem that puzzled me is that when we use the Gibbs sampling, we always sample randomly from the conditional probability. What will happen if we sample the most probable value instead? Thank you in advance.</p> | g26540 | [
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<p>Newbie question here. I am building a toy decision tree to differentiate personal names from business, government, or organizational names, like:</p>
<p>AAA ENTERPRISES LLC DBA AAA BBB SERVICE<br>
SMITH BARBARA<br>
EXAMPLE FLOOR COVERINGS<br>
BROWN JOSEPH A<br>
2013 HOLDINGS L L C</p>
<p>I'm mainly using continuo... | g67149 | [
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<p>In a effort to reduce human intervention, I'm trying to optimize the process of assigning bank transactions to invoices.
This task should be done once every year, so we can assume our dataset won't take more much more than 200 entities.
About our invoices, they are already categorized, for example as "Water expense... | g67150 | [
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<p>I hope that someone will be willing to help me with the following question. I have data on the numbers of hours participants spent in 6 programs over 2 years. I have already tested whether the number of hours increased over time, but I also want to know whether the proportion of time spent in each of the programs ch... | g26542 | [
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<p>In R, the logistic regression output gives you predicted probabilities. Is there away of determining the threshold value $\alpha$, such that any $p > \alpha$ is classified as a $1$ and and $p \leq \alpha$ is classified as a $0$? Can the <code> caret </code> package do this? </p> | g49768 | [
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<p>I have trained linear discriminant analysis (LDA) classifiers for three classes of the IRIS data and struggling with how to make the classification. Here is the procedure:</p>
<p>For the Iris data, I have 3 combinations i.e. (0,1), (0,2) and (1,2). So, I trained a simple binary LDA classifier for each combination, ... | g67151 | [
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<p>I have a dataset, which is based of a log.The data is as following:</p>
<pre><code> bid LOGIN UPDATE_BILLING CREDITCARD_APPROVED CREDITCARD_DECLINED UPDATE_MONTHLY_BUDGET CREATE_AD UPDATE_AD_BID UPDATE_AD_BUDGET UPDATE_AD PAUSE_AD
1 -1 0 0 0 0 ... | g67152 | [
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<p>I am interested in building a model to predict the binary outcome, retention (1 - retained; 0 - not retained) with various potential predictor variables (either continuous or categorical). </p>
<p>With that being said, I have a dataset containing multiple records (magazine subscriptions) for some subjects. For exam... | g67153 | [
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<p>My results of a Pearson's Correlation are shown below:</p>
<pre><code>Pearson’s Correlation – Test for Association
Pearson's product-moment correlation:
Test statistic: r = -0.1146235
Degrees of freedom = 363
Statistical significance: P = 0.02855
</code></pre>
<p>Reject null hypothesis, there is a small negative... | g26547 | [
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<p>Where X ~ a symmetric Student T Distribution $t_\alpha$, with power law tail $\alpha>2$, looking for the distribution of $\frac{(\sum_{i=1}^n x_i ^2 )^{½}}{\sum_{i=1}^n |x_i|}$, in order to estimate the properties of the statistic STD/MAD for a sample size $n$.</p>
<p>The problem is that both measures, MAD and ... | g67154 | [
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... |
<p>I am trying to do a weighted multiple least squares regression on utility data.
Basically I have utility bills where I use : Days billed, Consumption. For the same billing period I calculate Heating Degree Days and Cooling Degree Days.</p>
<p>$ HDD = (18-Tout)^{+} $ and $ CDD = (Tout - 21)^{+}$</p>
<p>Where the +... | g67155 | [
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<p>I have a ranked list say A,B,C,D,E,F,G and a subset of this list ranked with another strategy
lets say D,B,C,F. And my assumption is that the strategy used for ranking the sublist is better because its a feedback strategy. Now I want to re-rank my initial ranked list according to feedback ranking of sublist and ini... | g26551 | [
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0.0783529058098793,
0.00890304334461689,
0.06862471997737885,
0.06821155548095703,
0.024... |
<p>I have used a Tukey post-hoc test after seeing that the ANOVA test indicated some significant differences between my groups (A,B,C,D). I am somewhat confused about the results.</p>
<p><img src="http://i.stack.imgur.com/cERWq.png" alt="Plot and results"></p>
<p>Why, for example, is A significantly different from B ... | g26552 | [
-0.025103334337472916,
-0.038018565624952316,
-0.004331044852733612,
-0.022068938240408897,
-0.017743388190865517,
-0.008500047959387302,
0.06678574532270432,
0.021358825266361237,
-0.043308984488248825,
0.02522449940443039,
0.004474471788853407,
0.008765018545091152,
-0.006140235345810652,
... |
<p>I have conducted an experiment with multiple (categorical) conditions per subject, and multiple subject measurements.</p>
<p>My data-frame in short: A subject has one property, <code>is_frisian</code> which is either 0 or 1 depending on the subject. And it is tested for two conditions, <code>person</code> and <code... | g67156 | [
0.03764522448182106,
-0.031800881028175354,
-0.029433751478791237,
-0.012778746895492077,
-0.02759065106511116,
0.021294383332133293,
0.017303479835391045,
-0.031153084710240364,
-0.04622726887464523,
-0.056626200675964355,
0.018306709825992584,
0.017469899728894234,
0.05309247598052025,
-... |
<p>I have just begun studying survival analysis and I am using it for an industrial problem where I am trying to build survival curves for customer liftimes (from when they sign-up to when they cancel). I am using the Aalen additive model using explanatory variables that I think affect the customer lifetime. </p>
<p... | g67157 | [
-0.0038689805660396814,
-0.03237192705273628,
-0.008276281878352165,
0.0205400250852108,
-0.03154774755239487,
-0.020259620621800423,
0.10029980540275574,
0.008073615841567516,
-0.042056549340486526,
0.052926577627658844,
0.017233679071068764,
0.010208035819232464,
0.08110123872756958,
-0.... |
<p>I want to compare data from a treatment group vs a control group over time (baseline, 1 yr, 2 yr).</p>
<p>The measurements are repeated for all subjects across all time points (i.e., all participants complete the same set of questionnaires at all time points).</p>
<p>Some participants have missing data (some did n... | g67158 | [
-0.0061710309237241745,
-0.06902549415826797,
0.011515477672219276,
-0.0015052711823955178,
0.02907000109553337,
0.01757875643670559,
0.025649361312389374,
-0.01730194129049778,
-0.0074183205142617226,
0.02646377496421337,
0.03583560511469841,
-0.055388160049915314,
-0.026723302900791168,
... |
<p>Suppose I want to test the hypothesis that speed of light is always below $c$ (note: regardless of the medium). [Also, this is just a fake example, so pretend we don't know any physics theory]</p>
<p>Now, I did measurements of speed of light in 30 different mediums. Suppose the readings come with error (Gaussian wi... | g67159 | [
0.030591683462262154,
-0.04208981618285179,
0.0031131242867559195,
-0.002859510714188218,
0.03661229833960533,
0.015609628520905972,
0.024485375732183456,
-0.014298907481133938,
-0.04401686415076256,
-0.029805462807416916,
0.035005707293748856,
0.025850540027022362,
0.005857320036739111,
0... |
<p>For example, I have a series of values for example like the following:</p>
<pre><code>data <- c(rnorm(10000,40,1500),rnorm(9000,-35,1400),rnorm(11000,30,1300))
</code></pre>
<p>I don't know the mean, don't know the sd of my data, and am particularly interested in the "sign of the mean" of my data (I can do a t-... | g67160 | [
0.004161726217716932,
0.002416325267404318,
-0.031078269705176353,
-0.0677117183804512,
-0.022400490939617157,
-0.06516285240650177,
0.07389167696237564,
-0.003183465451002121,
-0.06955418735742569,
0.007455316837877035,
-0.026444146409630775,
0.06028496474027634,
0.05038775876164436,
0.01... |
<p>I would like to analyse the trajectories of patients hospitalized for CVA (cerebrovascular accident) with the package TraMineR.
I have a large dataset with around 25,000 trajectories observed during 365 days.
There are 5 states in my data.
When I try to use the seqdist function which computes the distances between s... | g26555 | [
0.012601382099092007,
0.024420950561761856,
-0.015587883070111275,
-0.032706599682569504,
-0.038006287068128586,
-0.05803360044956207,
0.07712958753108978,
0.027216240763664246,
-0.0325494147837162,
0.012633559294044971,
-0.02341010794043541,
-0.06250140070915222,
0.07920905202627182,
-0.0... |
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