question stringlengths 37 38.8k | group_id stringlengths 2 6 | sentence_embeddings listlengths 768 768 |
|---|---|---|
<p>I am trying to understand the logic behind chi-squared test.</p>
<p>The Chi-squared test is $\chi ^2 = \sum \frac{(obs-exp)^2}{exp}$. $\chi ^2$ is then compared to a Chi-squared distribution to find out a p.value in order to reject or not the null hypothesis. $H_0$: the observations come from the distribution we us... | g661 | [
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<p>I'm trying to understand conjugate families of distributions, and am hoping someone could give me a hint or direct to a good paper (or book) covering basics. </p>
<p>Or perhaps, simple example would help? <br>
Let's assume Gaussian model with both mean and variance random. <br> Uniform sample of the universe, say,... | g64006 | [
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<p>I have a bunch of time series where the data has a natural (known) cycle, for example daily or annual (or both). Here is an example (this is 6 years worth of temperature data sampled hourly):</p>
<p><img src="http://i.stack.imgur.com/MzxpY.png" alt="enter image description here"></p>
<p>Source data: <a href="http... | g21957 | [
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<p>I have a binomial variable that I regress against different categorical variables which I have contrasted to build a reference of an individual Female, Married, aged 35-45, High education :</p>
<pre><code>Call:
glm(formula = wpti ~ gender.f + is.married.f + age.f + edu.f,
family = binomial(link = "logit"))
Coeffi... | g21958 | [
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<p>I have a very silly question. In Multinomial Naive Bayes Classifier, which parameter estimation do we use, is it Maximum Likelihood or Maximum A Posteriori?</p>
<p>If any one of the esteemed members may kindly help me out.</p> | g64007 | [
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<p>For example, when estimating the proportion of database records that agree with paper documentation. Auditing each record is tedious, so it is tempting to include the pilot sample in the main study (once the required main sample size is estimated). Provided the sampling method is the same, does this introduce bias... | g64008 | [
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<p>I have found that in much of the data that I am looking through, after sorting from largest to smallest, there is a pattern similar to a rotated logistic function. That is, it declines steeply along the vertical axis at first, evens out, and then continues to decline along the vertical axis at the same rate as it d... | g21960 | [
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<p>ANOVA Test is used on mean score of individual studies' parametric estimates with fixed and Known population or random unknown population.</p> | g49640 | [
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<p>When considering time dependent data in survival analysis, you have multiple start-stop times for an individual subject with measurements for the covariates. If each season has a different size (for example: repr=90 days,post_r=5,winter=23), the probability of an individual dying in repr it's largest. </p>
<p>How... | g21963 | [
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<p>How to measure the "goodness of fit" in generalized linear models for repeated measures. To make clear: I'm searching for something which is based on the (deviance) residuals, something like an adj. R^2 for linear models. Something that could make me state about the efficacy of the model? Any thought would be apprec... | g21965 | [
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<p>It appears that reliability and construct validity have a similar backing in terms of statistics. Is it true ?</p> | g64009 | [
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<p>I was reading Koller's book of probabilistic graphical models and in section 3.3.2 she discusses what properties should hold for d-separation as a method for determining independence. She tries to motivate that hopefully, separation should be sound and complete. <em>Sound</em> in the sense that, if we have that two ... | g64010 | [
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<p>I'd like to test for and estimate group differences in NIHSS (National Institute of Health Stroke Scale) change between hospital discharge and three months after hospital discharge.</p>
<p>Because the score is bounded between 0 and 42, the signed difference between the two measurements seems to me inappropriate, as... | g37683 | [
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<p>Traditionally, the individual coefficient significance test can be solved by applying t-test. However, in my case, as follows:</p>
<ol>
<li>the predictor values have been standardized</li>
<li>the standardized coefficient have been known</li>
<li>we would not know the values of predictors, thus we can not use the t... | g64011 | [
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<p>Suppose that I have a time series, $x_{1:n}$, and I would like to test whether they are all independent samples from the uniform distribution on $[0,1]$. This is a somewhat basic question, but how do I correctly test for that? </p>
<p>I am using the Kolmogorov-Smirnov test to check that they are uniform.</p>
<p>On... | g37509 | [
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<p>I have $K$ datasets, each with $N$ variables and $M$ samples (they are in fact EEG time series, but I discard time and treat them as $K$ iid multivariate samples) and assume they are coming from the same multivariate normal distribution.</p>
<p>I am interested in estimating the covariance matrix. Now it can be done... | g64012 | [
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<p>I am reading Huber's Robust Statistics (2nd). On page 2 and 3 he gave an example. The basic facts are summarized here. Let $(X_n)$ be a sequence of random variables and define two measures of spread as follows.</p>
<ol>
<li>Mean Absolute Deviation: $d_n := \frac{1}{n}\sum|x_i-\bar x|$.</li>
<li>Standard Deviation: ... | g64013 | [
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<p>This is more of a history of science question, but I hope it's on-topic here.</p>
<p>I've read that Thomas Bayes only managed to discover Bayes' theorem for the special case of a uniform prior, and even then he struggled with it, apparently.</p>
<p>Considering how trivial the general Bayes' theorem is in modern tr... | g64014 | [
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<p>I have data about popularity of some products in some stores. For each of the stores I have only a ordered rank of best-selling products in them. I need help how to find information about which products are popular only in certain stores versus products that are popular in all stores.</p> | g64015 | [
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<p><img src="http://i.stack.imgur.com/1amt2.png" alt="enter image description here"></p>
<p>What I have so far is this:</p>
<p>I need to find the E[.] and V[.] and show that the expected value equals to $\sigma^2$ and variance tends to 0 as T -> $\infty$. I already found the Expected value to be equal to $\sigma^2$.... | g64016 | [
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<p>I am a little bit confused about the concept of "well calibrated <strong>tests</strong>" -- what aspects are we referring to from <strong>a test</strong> if it is well calibrated? I tried to search some papers on such discussions or textbooks, but the results seem to be very subject-specific. Thank you for your clar... | g64017 | [
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<p>Are the concepts of descriptive vs inferential statistics and parametric vs non-parametric statistics orthogonal? As in, can we have a descriptive parametric statistic or a descriptive non-parametric statistic? if so what are some examples of? I know you can have an inferential parametric or non-parametric statistic... | g64018 | [
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<p>Imagine we have a list of ordered numbers $L = (1, 2,\dots, N)$.</p>
<p>I want to add an arbitrary amount of "disorder" to that list. For instance:</p>
<ul>
<li><p>Adding a little bit of disorder would permute a few neighboring numbers</p></li>
<li><p>Adding more disorder would permute several numbers, many of th... | g64019 | [
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<p>I’m trying to find a better way to analyse my data. </p>
<p>Unfortunately my limited background in math does not allow me to freely make a confident choice. I’ve already done an ANOVA, the method mostly used in our lab. As it often happens with statistics in non-statistical fields, it was chosen mainly based on the... | g21979 | [
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<p>I build a few models, each model will produce a normal distribution for the value of a future event. For example, model M1 will produce a normal distribution $n(30, 5^2)$, and the value of the future event observed is 24. Likewise,</p>
<p>M2-> $n(40, 10^2)$, observation: 35</p>
<p>M3-> $n(10, 2^2)$, observation: 2... | g49688 | [
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<p>I have some data values of type date/time (the last date that a resource was accessed) and I wish to chart this data on the y-axis against the different categories of resource on the x-axis.</p>
<p>What would be a sensible type of chart for displaying this sort of data ? For example is a histogram / bar chart sat... | g64020 | [
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<p>Can anyone recommend some books that are considered to be standard references for classical (frequentist) statistics? IE, fairly comprehensive, and also, been around for a while so that typos and mistakes in formulas had a chance to be checked and corrected</p> | g64021 | [
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<p>I would like to solve <a href="http://projecteuler.net/index.php?section=problems&id=213" rel="nofollow">Project Euler 213</a> but don't know where to start because I'm a layperson in the field of Statistics, notice that an accurate answer is required so the Monte Carlo method won't work. Could you recommend som... | g64022 | [
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<p>Suppose a gambler makes a series of independent bets. In each bet, there's a 50% chance that he loses $\$100$.</p>
<p>If he wins, he has an option to take $\$100$ or run a "winner's bet", instead of taking that reward. In the winner's bet, there is a 60% chance to win 50 dollars, a 30% chance to win 150 dollars, an... | g64023 | [
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<p>(Please note the cross-post at <a href="http://stackoverflow.com/questions/7626347/difference-between-lp-or-simply-in-rs-locfit">http://stackoverflow.com/questions/7626347/difference-between-lp-or-simply-in-rs-locfit</a>)</p>
<p>I am not sure I see the difference between different examples for local logistic regres... | g41442 | [
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<p>I've created this toy example to demonstrate something that is occurring with my real data. I do not understand how to interpret the apparent failure of cv.glmnet to find a solution when it's explicitly "doped" into the data.</p>
<p>Let's create a matrix of random predictors:</p>
<p>xtrain = replicate(100,rnorm(1... | g16893 | [
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<p>This question just occurred to me out of the blue. PCA is a way to reduce dimensions. Another way that is often (perhaps too often) used is to take mean values of two or more variables. This is done a great deal to create "scales" or "ratings" that get published in the popular press about various political issues. D... | g21987 | [
0.02149931527674198,
-0.029549943283200264,
0.004619873594492674,
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0.03369717299938202,
0.009085779078304768,
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0.011796998791396618,
0.0449431873857975,
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0.037319738417863846,
0.051... |
<p>I got measures of one variable (that behaves as a time series) for different conditions (some quantitatives, but mostly are qualitatives).</p>
<p>For example, this is a "fake" representative plot of this variable for 2 differents conditions :</p>
<p><a href="http://www.casimages.com/img.php?i=140415020040937841.pn... | g64024 | [
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0.018885165452957153,
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0.025589071214199066,
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<p>I want to derive the limits for the $100(1-\alpha)\%$ confidence interval for the ratio of two means.<br>
Suppose, $X_1 \sim N(\theta_1, \sigma^2)$ and $X_2 \sim N(\theta_2, \sigma^2)$
being independent, the mean ratio $\Gamma = \theta_1/\theta_2$. I tried to solve:
$$\text{Pr}(-z(\alpha/2)) \leq X_1 - \Gamma X_2 / ... | g21988 | [
-0.025458628311753273,
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0.011968511156737804,
0.01647639088332653,
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... |
<p>I need a test to check for homogeneity of variances. I am not sure if a series is normally distributed.</p>
<ul>
<li>If I use a test of homogeneity of variance that works for NON-normally distributed data, does the series also pass (with "pass" I mean that the variances ARE homogeneous) if the distribution is norma... | g41445 | [
0.016314564272761345,
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0.0... |
<p>Are there any free econometrics textbooks available online for individual use? </p>
<p>I'm aware of Bruce Hansen's first year PhD <a href="http://www.ssc.wisc.edu/~bhansen/econometrics/" rel="nofollow">Econometrics</a> textbook, but I'd be interested to hear if there are any other such resources.</p>
<p>Note:
Thi... | g64025 | [
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0.03313827887177467,
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0.033994562923908234,
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<p>I use a standard GARCH model:
\begin{align}
r_t=\sigma_t\epsilon_t\\
\sigma^2_t=\gamma_0 + \gamma_1 a_{t-1}^2 + \delta_1 \sigma^2_{t-1}
\end{align}</p>
<p>and $a_t=\sigma_t\,\epsilon_t$</p>
<p>I have different estimates of the coefficients and I need to interpret them. Therefore I am wondering about a nice interpr... | g21989 | [
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0.031524237245321274,
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0.04760017991065979,
0.026599381119012833,
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<p>I have a population with age range 0-6 years old. A survey asked various "Choose all that apply" questions and I'd like to compare the age densities for each subset (Did choose option X, Did Not choose option X), to look for age ranges where significant differences appear to have occurred.</p>
<p>The reported ages ... | g10503 | [
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-0.... |
<p>If $K_1, \dots, K_n$ are i.i.d. Poisson distributions with parameter $\beta$ I have worked out that the maximum likelihood estimate is $$\hat\beta (k_1, \dots, k_n) = \frac{1}{n} \sum_{i=1}^n k_i$$ for data $k_1, \dots, k_n$. Therefore we can define the corresponding estimator $$T = \frac{1}{n} \sum_{i=1}^n K_i .$$... | g64026 | [
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... |
<p>I have two random variables following normal distributions,
$X\sim N(\mu_{x},\sigma_{x})$
and
$Y\sim N(\mu_{y},\sigma_{y})$</p>
<p>I know the covariance is $\operatorname{Cov}(X,Y) = c$.</p>
<p>And I believe (correct me if I'm wrong) that I can estimate the expected value of $Y$ given $X=\tau$ as follows:</p>
<p>... | g64027 | [
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<p>I have values for <code>True Positive (TP)</code> and <code>False Negative (FN)</code> as follows:</p>
<pre><code>TP = 0.25
FN = 0.75
</code></pre>
<p>From those values, can we calculate <code>False Positive (FP)</code> and <code>True Negative (TN)</code>?</p> | g64028 | [
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<p>I'm working on a model with multiple covariates in R. Unfortunately, for one of the factors in the model, the data is spotty and I have a large portion of unknown values. Rouhgly around 30% are NA's. Is it recommended to simply remove these individuals from the model (I believe this is what R does by default, "10,12... | g64029 | [
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<p>I have the (not necessarily veridical) impression that typical textbook independence tests of proportions are intended for use the proportions involved are not super small.</p>
<p>In my case n may be 10^8 but the count of successes may be 10^4.</p>
<p>N per group may also differ, which of course means the sample v... | g21998 | [
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... |
<p>I am teaching undergrad computer security and look for a semi-formal way to make students understand the notion of a <a href="http://en.wikipedia.org/wiki/One-time_pad" rel="nofollow">one-time pad</a> (OTP). To this end, consider the following exercise:</p>
<blockquote>
<p>Suppose you want to encrypt a message $M... | g41454 | [
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0.03631186485290527,
0.002286161296069622,
0.00582... |
<p>I'm new to statistics and recently I learnt about non-parametric estimation. On the estimation of empirical quantiles, many notes talk about the asymptotic behavior of sample quantiles. The proof is based on the consistency of the empirical quantile estimator, then applying Slutsky's theorem in combination with the ... | g64030 | [
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<p>I have a general knowledge of regression, but I don't know what is the best approach to analyze these data. The dataset represents quarterly rates of inpatient use for three provider groups <code>prov1</code>, <code>prov2</code> and <code>prov3</code>. The rates were measured on quarterly basis from <code>qrt-4 2005... | g64031 | [
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<p>I have a lot of wonderfully messy data (got to love the social sciences), and realized that I was not fully prepared to bear its wrath.</p>
<p>For the record, after reading some articles regarding ANOVA, I am extremely paranoid about violating its assumptions. So I am trying to do my best in cleaning the data. I ha... | g64032 | [
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<p>Good day!
I'm using R and I have a panel dataset of 72 countries x 19 years x 6 parameters. The current mini-goal is to estimate following equation:
<img src="http://i.stack.imgur.com/0Yit8.png" alt="enter image description here"></p>
<p>The problem is that <em>beta</em> doesn't have an <em>i</em> index, so the mod... | g64033 | [
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... |
<p>I ran a Confirmatory Factor Analysis (CFA) in Amos and obtained a model with high covariance between the factors. James described this covariance in his <a href="https://www.youtube.com/watch?v=MCYmyzRZnIY#t=2m48" rel="nofollow">video</a> as alarming.</p>
<p>What can I do to tackle this problem? All my factor loadi... | g64034 | [
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<p>Does someone know how the "best" split at a node is determined in the <a href="https://code.google.com/p/randomforest-matlab/" rel="nofollow">MATLAB RF package</a>?</p>
<p>I have more than two classes, and just wondered how it is working. Is the package using the Gini impurity? (Well I would not know exactly how th... | g64035 | [
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0... |
<p>Suppose you have a new algorithm that you want to publish. Are there any best practices and methodologies you usually consider in order to test the robustness and performance of a new method?</p>
<p>The case is a novel classification algorithm of matrices composed by observations x features (e.g. a gene expression ... | g64036 | [
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0.021954648196697235,
0.06724322587251663,
0.023679139092564583,
0.07921169698238373,
0.02... |
<p>I'm using k-fold cross-validation to compare different models.</p>
<p>I splitted my dataset in 6 chunks and used 4 random chunks as training set and the remaining 2 as a test set.</p>
<p>Now I fitted n-different models to the training set and calculated the RMSE on both the training and the test sets. From what I ... | g22003 | [
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0.0015560789033770561,
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0.01707320... |
<p>I'm hoping that someone can explain, in layman's terms, what a characteristic function is and how it is used in practice. I've read that it is the Fourier transform of the pdf, so I guess I know <em>what</em> it is, but I still don't understand its purpose. If someone could provide an intuitive description of its pu... | g41459 | [
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0.0013811649987474084,
0.0564696341753006,
0.0031... |
<p>I am modeling Diabetes Prediction using Logistic Regression. The dataset used is the <a href="http://www.cdc.gov/BRFSS/" rel="nofollow">Behavioral Risk Factor Surveillance System (BRFSS)</a> of the Center for Disease Control (CDC). One of the independent variables is High Blood Pressure. It is categorical with the ... | g64037 | [
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0.02134707197546959,
0.05576735734939575,
0.03718286007642746,
0.... |
<p>I wonder if two identical time series are cointegrated. Can anyone shed some light on this? Thanks</p> | g22006 | [
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0.04000752046704292,
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0.03716108947992325,
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<p>I want to perform spectral analysis and was wondering if this command in R:</p>
<pre><code>out=mvspec(data,detrend=TRUE,log="yes")
</code></pre>
<p>displays the detrended log-periodogram. Also would the cepstrum be the frequency with the highest amplitude?</p> | g64038 | [
0.0427350290119648,
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<p>I want to model the outcome of a binary dependent variable D over a large universe [many records, 100s of variables].</p>
<p>Given a fixed sample size, I want to maximize the accuracy of the model over the universe. I already have some information about the nature of D that I want to use. </p>
<p>When binary varia... | g64039 | [
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0.03920309990644455,
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0.05067451670765877,
0... |
<p>Is there such a formula? Given a set of data for which the mean, variance, skewness and kurtosis is known, or can be measured, is there a single formula which can be used to calculate the probability density of a value assumed to come from the aforementioned data?</p> | g64040 | [
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<p>Consider the following model:</p>
<ul>
<li>$wage_i=\beta_0+\beta_1after_i+\beta_2female_i+\beta_3after_ifemale_i+u_i$</li>
</ul>
<p>where</p>
<ul>
<li><p>$after_i=1$ if date after gender-wage discrimination policy; $0$ if date before gender-wage discrimination policy.</p></li>
<li><p>$female_i=1$ if female; $0$ i... | g64041 | [
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<p><img src="http://i.stack.imgur.com/9RaBO.png" alt="Question"></p>
<p>So first this question asks "how I would discriminate between model(1) and model(2)".</p>
<p>It appears that both models are non-nested so I would come up with a hybrid model consisting of Xt,Zt and Qt regressors. I know I need to test for Zt=0 a... | g22010 | [
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0.0672781690955162,
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<p>I'm reinterpreting the data of some colleagues to see if I can't get at heterogeneity in grouped outcomes. Start with a decay process with two pools:</p>
<p>$$
C_{it} = P_i e^{-k_{i}^{fast}t} + (1-P_i)e^{-k_i^{slow}t}
$$</p>
<p>The amount of $C$ remaining in situation $i$ after time $t$ is an exponential function... | g64042 | [
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0.015562144108116627,
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0.04... |
<p>I am trying to build a model of 7 classes text documents. </p>
<p>However, i do not have equal number of samples for each class. I can have close to about 10k documents for class A but only about 100 samples for class E. How is it possible that I can improve my model. I am achieving about 80% accuracy currently.</p... | g64043 | [
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<p>I want to know if moose are crossing water more than expected. I followed the methods written in Beyer et al 2013 which I am now completely confused as to how to actually do the analysis. I am hoping someone would be willing to help explain the steps - because I think i am simply overly complicating it or I am mis... | g22012 | [
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<p>According to my book, for a random sample $(X_1, \ldots, X_n)$ from a continuous distribution with p.d.f. $f(x)$ and c.d.f. $F(x)$, the p.d.f. of the maximum of the sample is $g(z)=nf(z)[F(z)]^{n-1}$, where $z=\mathrm{max}(x_1, \ldots,x_n)$. The book gives the following question: </p>
<blockquote>
<p>the random v... | g64044 | [
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<p>I have a large dataset consisting of many features for each record which includes either a GOOD or BAD outcome. Three metrics have been created for classification purposes using three respective Bayesian Belief Networks:</p>
<ul>
<li>Classification Network including outcome variable trained on both GOOD and BAD rec... | g22013 | [
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<p>I am performing simple (first-order terms) linear regression on data having several categorical variables (i.e. factors), and it is often desired that for each factor, one of the levels should add nothing to the regressand, and the other levels should add positive values to the regressand. When I perform a regressi... | g37472 | [
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<p>I want to see if certain factors affect overall customer satisfaction for a specific program. My response would be customer satisfaction ratings, where a <strong>0=not satisfied</strong> and <strong>1=satisfied</strong>. If my factors follow the same scale, can I use a factorial design to test whether the factors ha... | g22015 | [
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<p>Imagine you were interested in student dropout rates across schools over time. You had data on the number of dropouts, but not the number of students enrolled at each school-month.</p>
<p>A single dropout for a school with 10 students is a higher relative rate than 2 dropouts in a school of a 100.</p>
<p>An increa... | g64045 | [
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<p>I have an unbalanced repeated measures data set to analyse, and I've read that the way most statistical packages handle this with ANOVA (i.e. type III sum of squares) is wrong. Therefore, I would like to use a mixed effects model to analyse these data. I have read a lot about mixed models in <code>R</code>, but I am... | g64046 | [
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<p>Assuming that I have a one-dimensional data set with a known distribution (i.e. normal, gamma, Weibull, etc.), is there a R function that I can call on the data set that will return the anomalies?</p>
<p>I know that anomaly detection in a known normally distributed data set is pretty straightforward but I couldn't ... | g64047 | [
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<p>I have a problem which I am trying to fit into a classical regression/learning framework.</p>
<p>I have a dataset $D$ where each instance $d_i$ is a set of $(x,y)$ pairs, where $x$ is a non-negative number representing a position and $y$ is a non-negative value. For example, one $d_i$ could look like this:</p>
<p>... | g64048 | [
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<p>I have the following data set:</p>
<pre><code>Row Patient Freq of Sickness Sick # of times(2 yrs) Symp 1 Symp 2 Sym 3
1 A 60 days 4 1 0 1
2 B 90 days 10 0 ... | g64049 | [
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<p>What are the panel's recommendations for books on design of experiments?</p>
<p>Ideally, books should be still in print or available electronically, although that may not always be feasible. If you feel moved to add a few words on what's so good about the book that would be great too.</p>
<p>Also, aim for one book... | g49563 | [
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<p>I'm trying to better understand some of the theory behind fitting models that have a nonlinear link between the response and the predictors. </p>
<pre><code>set.seed(1)
#Create a random exponential sample
n<-1000
y<-rexp(n=n,rate=.01)
y<-y[order(y)]
x<-seq(n)
df1<-data.frame(cbind(x,y))
plot(x,y)
</... | g64050 | [
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<p>I wonder if feature scaling like this makes always sense for neural networks:</p>
<p>Let $T$ be the training set and $x_i \in \mathbb{R}^n$ with $d_i \in T$ be the feature vector of $d_i$. Then add another preprocessing step so that $x_i' \gets \frac{x_i - \text{mean}(T)}{\max(T) - \min(T)}$ where $\max$ and $\min$... | g64051 | [
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... |
<p>One of the most important issues in using factor analysis is its interpretation. Factor analysis often uses factor rotation to enhance its interpretation. After a satisfactory rotation, the rotated factor loading matrix <strong>L'</strong> will have the same ability to represent the correlation matrix and it can be ... | g64052 | [
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<p>I have two implementations of a genetic algorithm which are supposed to behave equivalently. However due to technical restrictions which cannot be resolved their output is not exactly the same, given the same input.</p>
<p>Still I'd like to show that there is no significant performance difference.</p>
<p>I have 20... | g22019 | [
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0.03854312747716904,
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0.0... |
<p>I need some help about repeated measurement ANOVA.</p>
<p>We are investigating the effect of some intervention on reducing blood stream infection (BSI) rate in some wards. We plan to capture the BSI rate information at a monthly basis, 12 months without intervention first, then 12 months with intervention.</p>
<p>... | g46637 | [
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<p>Reading lof implementation at : <a href="http://www.cse.ust.hk/~leichen/courses/msc-it5210/lectures/LOF_Example.pdf" rel="nofollow">http://www.cse.ust.hk/~leichen/courses/msc-it5210/lectures/LOF_Example.pdf</a></p>
<p>the local reachability distance is given as : </p>
<p><img src="http://i.stack.imgur.com/bcEjP.pn... | g64053 | [
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<p>I am using Rminc to calculate the W value for an analysis with group sizes of 6 and 19. I then get some W values (from 1-114), but how can I calculate the associated p-value from the W-Value?</p> | g64054 | [
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0.05291306972503662... |
<p>I am interested in estimating a regression that looks like this: </p>
<p>$(x_{1,i} - y_{i} )_{i} = x’_{i}*\beta + \epsilon_{i}$ <strong>(1)</strong></p>
<p>However, I am not sure if doing this—in this form—is appropriate. The reason for this is that $y_{i}$ and $x_{1,i}$ are correlated. Put differently, $x_{1... | g64055 | [
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0.0041130948811769485,
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0.041884176433086395,
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<p>what is the best (and easy) way to detect outliers in spss for skewed, not exactly normally distributed data?</p>
<p>Thanks a lot</p> | g64056 | [
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<p>I'm looking into some classification tasks at the moment. The test data is unbalanced where one particular class is half the data and the remaining 5 take up the remainder of the test data. When I look at the output for some of the classifiers I notice that the AUC is over .8 while the TPR and FPR might be something... | g64057 | [
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<p>I have a set of probabilities that an event will occur (yes/no). E.g. [0.87, 0.56, 0.97], and I need to know "What is that probability that at least X of these events occurs?". I've been looking into Binomial Probability Density and related tests, but they all seem to assume that the probabilities for each event are... | g64058 | [
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-... |
<p>I have data with which I plot a histogram.</p>
<p>I would like to know the standard deviation of each bar of histogram.</p>
<p>Do you think it is an acceptable method to divide the samples into sub-samples for which I calculate the height of a bar (and so I will get a new sample of heights), and with this new samp... | g49689 | [
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<p>I am writing a programme to simulate the age at which women will get breast cancer. I have data on the cumulative incidence rate for the whole population.</p>
<p>What I am doing right now is using Monte Carlo methods at every 5 year age step from 0 years old to the age of women have cancer. But this seems stupid an... | g64059 | [
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<p>I hope I am able to word my question clearly. Suppose I have a model below:</p>
<pre><code>glmer(Y~X + (1|subject), family="binomial", data=dat)
</code></pre>
<p>The intercept is the log odds of success for the reference level (level 1 of X), and the slopes indicate the log odds ratio of the other levels to the re... | g64060 | [
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<p>I'm looking to obtain standard errors for constrained linear model estimation. I'd like to be able to estimate standard errors and confidence intervals for the coefficients of $\beta'$ estimated via:</p>
<p>$$
\beta' = \underset{\beta}{\operatorname{arg\,min}} \, (\mathbf{y} -\mathbf{X}\mathbf{\beta})^2 \ \ \ s.t.\... | g64061 | [
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<p>Suppose we are modeling the probability of heads on a biased coin. We use observable features, for example, its shape and color. We train a logistic regression classifier on a bunch of known coins with known probability distributions and use it to predict the probability $p$ a new coin would come out heads.</p>
<p>... | g64062 | [
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-... |
<p>Background: </p>
<p>I am using Bayesian inference to find a posterior density. The parameters are change points in a piecewise Wiener process, and I wish to calculate the hitting time of some threshold $a$. The hitting time of a (not piecewise) Wiener process is Inverse Gaussian distributed. The change points are e... | g10513 | [
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<p>I say 'mode' in the title – perhaps there's something more appropriate I can find. Here's my problem:</p>
<p>A person is in a $100\mathrm m$ by $500\mathrm m$ space.</p>
<p>I have about 100 samples randomly distributed in that space. Each sample is the relative probability that the person is at that point.</p>
<p... | g64063 | [
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... |
<p>Suppose I have some survey data on which I'd like to conduct an analysis
similar to this:<br>
<a href="http://yangclaireyang.web.unc.edu/research/age-period-cohort-analysis-new-models-methods-and-empirical-applications/chapter-7/" rel="nofollow">Yang, <em>Age-period-cohort analysis</em>, Ch 7</a>.</p>
<p>Suppose fu... | g10514 | [
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0.02498573064804077,
0.0069952066987752914,
-0.010150200687348843,
0.01563825085759163,
0.034948352724313736,
0.027174539864063263,
-0.07002779841423035,
0.02131141535937786,
0.... |
<p>3 random variables have equal pairwise correlation, what are the possible values of correlation?</p>
<p>I think 1 and 0 are the obvious answers, but are there any more, and how could I find them?</p> | g49690 | [
-0.018868297338485718,
0.0021466873586177826,
0.0005192169337533414,
-0.039267439395189285,
0.02850583754479885,
0.0025809728540480137,
-0.0414823479950428,
0.007248089648783207,
-0.011403308250010014,
-0.0015590798575431108,
-0.039175763726234436,
-0.005448136944323778,
-0.0450056716799736,... |
<p>Is there a way to convert both, Spearman's $\rho$, and Cramér's V into the same effect size (f.e. Cohen's $d$), in order to have an information about which of the underlying relationships (nominal&ordinal --> Cramér's V; ordinal&ordinal --> Spearman's $\rho$) is stronger?</p>
<p>Fictitious example:
(a) Spea... | g64064 | [
0.03946151211857796,
-0.02054603025317192,
-0.02391834929585457,
-0.09608457237482071,
0.01948358118534088,
-0.05372719094157219,
0.01354505866765976,
-0.020719904452562332,
-0.0035879467613995075,
0.017691856250166893,
0.04306633397936821,
0.05356056988239288,
0.004171342588961124,
0.0054... |
<p>I'm studying a stochastic process generated by simulation using two different methods. In the first, the waiting time between events can be shown to be exponentially distributed. To model the credibility interval for the rate of events, $k$, I'm using an analytic form of the posterior distribution generated with a u... | g17136 | [
0.02754639834165573,
0.0400671511888504,
0.013444911688566208,
-0.0197743009775877,
0.005522307474166155,
0.03151610866189003,
-0.02830875664949417,
0.027862567454576492,
-0.0167621448636055,
0.03137514740228653,
0.04320548474788666,
0.025993365794420242,
0.07126817852258682,
0.01802599988... |
<p>Is it possible to use R to predict the input or independent variables that lead to a particular value of the dependent variable? I have a linear model relating three input variables to a dependent variable. However, I would like to inverse the model so that now I can use it to predict the input variables. My inkling... | g64065 | [
-0.004145916551351547,
-0.08179520070552826,
-0.004189203027635813,
-0.03739423304796219,
-0.05678027495741844,
0.002893696306273341,
-0.008867104537785053,
0.022364940494298935,
-0.04627353325486183,
-0.008620224893093109,
-0.01577511616051197,
0.04171646386384964,
0.012543736025691032,
-... |
<p>I need to find the UMP of a random sample of a BETA$(\theta,1)$ distribution. I know that the pdf of this problem is
$$f(x;\theta)=\theta x^{\theta-1}=\theta e^{(\theta-1)\log{x}}$$
After some calculations i get to the point that i know this family contains a MLR for $\sum_{i=1}^n\log{x_i}$. This is were i get stuck... | g64066 | [
-0.004729845095425844,
0.00561976945027709,
-0.022044973447918892,
-0.01546148769557476,
0.017957912757992744,
-0.05373102426528931,
0.020226003602147102,
-0.012257125228643417,
-0.00601697014644742,
-0.01915702410042286,
-0.03807647153735161,
0.009864543564617634,
0.021788885816931725,
0.... |
<p>Suppose I have a very simple model of wages:</p>
<p>$w_t = \alpha + \beta_1p_t^e + \beta_2p_{t-1} + \beta_3u_t + \epsilon_t$</p>
<p>What are the ways of dealing with the price expectation?</p>
<p>I've thought about an adaptive expectations model, which I could recursively substitute, i.e.:
$p_t^e = \gamma p_{t-1}... | g64067 | [
-0.01874738186597824,
-0.008304369635879993,
-0.030211666598916054,
-0.0199941024184227,
0.032694462686777115,
-0.03435330092906952,
0.002130650682374835,
0.01198195293545723,
-0.041833169758319855,
0.014303142204880714,
-0.0110051603987813,
0.012961367145180702,
0.03338080272078514,
0.056... |
<p>I have come across a graph pattern in two basically unrelated experiments, and I want to understand where it is coming from, or at least how to handle it statistically.</p>
<p>I work in computational linguistics; I have picked up some statistics along the way, but barely enough to make grunt noises.</p>
<p>For eva... | g22034 | [
-0.005444924347102642,
0.020210297778248787,
-0.017853135243058205,
-0.08823774009943008,
-0.011046654544770718,
-0.06459388881921768,
-0.020436137914657593,
0.030108915641903877,
-0.03605992719531059,
-0.02272748574614525,
-0.02234293334186077,
0.022123217582702637,
0.09701073169708252,
-... |
<p>I have two vectors of data of different sample size. Both are the same experiment, but executed in a different environment. Since the sample sizes are different and they don't share any subject, is it safe to assume there is no dependency possible? From what I gathered, there can be no correlation nor can I create ... | g22035 | [
0.052826888859272,
-0.016992880031466484,
0.013850167393684387,
-0.041123781353235245,
-0.04081849381327629,
0.015872295945882797,
0.013925977051258087,
-0.035029541701078415,
-0.035031192004680634,
-0.06713588535785675,
0.02415088750422001,
0.00822509452700615,
-0.029619645327329636,
-0.0... |
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