question stringlengths 37 38.8k | group_id int64 0 74.5k |
|---|---|
<p>Given a dataset $D$ representing past history of a certain variable, is there a metric $\alpha(D)$ which determines whether the dataset can be forecasted or not, i.e. $\alpha(D)$ tells us whether $D$ is amenable to forecasting (with some reasonable degree of accuracy)? Any links or references would be appreciated. I... | 69,541 |
<p>I am training Restricted Boltzmann MAchine with MNIST Datasets. As per my understanding if it can reconstruct input proper then i will say it learnt. But, when i use Persistent Contrastive Divergence, it will not reconstruct proper because positive and negative phase samples doesnot match. In this case, how i will f... | 69,542 |
<p>I have estimated a multivariate regression line using OLS, and all 3 variables were found to be statistically significant.</p>
<p>$$d(NER)=.75+.08\times d(CA)+.002\times d(TB)-.003\times d(OFR)$$</p>
<p>Here, $NER=$ Nominal Exchange Rate (in No. of local currency exchange with $\$$1 USD), $CA=$ Net Capital Inflows... | 69,543 |
<p>I was working through the lab on ridge regression and LASSO in ISLR and I came across a strange behavior in the <code>cv.glmnet</code> function. When I followed the lab as written I got the following </p>
<pre><code>set.seed(1)
train <- sample(1:nrow(x), nrow(x)/2)
test <- (-train)
y.test <- y[test]
set.se... | 49,385 |
<p>I read Wikipedia which says that p-value is simply the area of distribution's tail. Wikipedia also says that to compute p-value of a normal distribution, <a href="http://en.wikipedia.org/wiki/Lindley%27s_paradox#Frequentist_approach" rel="nofollow">you integrate over the observed range rather than infinitely</a> (no... | 69,544 |
<p>I was just told <a href="http://stats.stackexchange.com/questions/67721/is-there-a-law-that-says-if-you-do-enough-trials-rare-things-happen#comment130858_67721">in comments</a> that probability p=1/n does not mean that I have 1 occurrence in n experiments in average, for large number of experiments because observed ... | 30,097 |
<p>Ok, this is a quite basic question, but I am a little bit confused. In my thesis I write:</p>
<p>The standard errors can be found by calculating the inverse of the square root of the diagonal elements of the (observed) Fisher Information matrix:</p>
<p>\begin{align*}
s_{\hat{\mu},\hat{\sigma}^2}=\frac{1}{\sqrt{\ma... | 30,098 |
<p>I have a question about performing stepwise regression. I realize that there are issues with using stepwise methods, but I have about 30 or so predictors and have constructed an <code>lm</code> object.</p>
<pre><code>m1 <- lm(LEADSforester ~ . , data=dat)
m2 <- lm(LEADSforester ~ 1 , data=dat)
step(m1, m2, di... | 30,099 |
<p>I have a model with occurrence of a disease represented by a binary dependent variable (DV) and 8 independent variables (IVs) at different levels. I need to create a multi-level model, in which the treatment is placed in the lower order and the demographics are in the higher order.</p>
<p>However, I am not familia... | 30,100 |
<p>I have a matrix (x) containing 55 samples (rows) and 10000 independent variables (columns). The observations are binary, healthy or ill {0,1} (y). I want to perform leave one out cross-validation and determine the Area Under Curve (AUC) for each of the variables. To do so I need the <code>nfold</code> parameter to b... | 69,545 |
<p>I have difficulties fitting a joint model in <code>R</code>. My data consists of two responses <code>X</code> & <code>Y</code> and one predictor variable <code>Z</code>. Now I want to model both <code>X</code> and <code>Y</code> in function of <code>Z</code> (just linear regression: $E(X|Z)=Z\alpha$ and $E(Y|Z)=... | 69,546 |
<p>I'm studying for my first statistics exam and I've been trying to calculate $P(X>5)$ for an event which is Poisson distributed. The Poisson distribution is defined as $P(X<5)$ in table in which I want to look up the correct numbers. I thought that $P(X>5)$ would be equal to $1-P(X<5)$ but the right answe... | 69,547 |
<p>Starting from a given sample, is it possible to estimate (roughly) automatically what kind of law the variable inducing this sample seems to follow?</p> | 69,548 |
<p>What is the qualitative difference between a first and second order Monte Carlo simulation, and the context in which one would implement each.</p> | 69,549 |
<p>I have a large set of data and a couple of regressors that seem to be somewhat to highly correlated. I will include these in a GLM and am primarily interested in the predictive ability of the model and not inference on individual parameter estimates.</p>
<p>How will the predictive ability of the model be influenced... | 69,550 |
<p>I have a list of diseases for my research. For each disease, I have a list of ages for the diseases. "Breast Carcinoma" may be a list of [1,2,2,3,4,5,5,5,5,5] while "Adrenal Cortex Neoplasms" maybe be a different list with a thousand elements, BUT with the same general shape in a bincount (high number of 5s, a few 2... | 69,551 |
<p>I want to test whether there are any significant differences between Public Relation Strategies of the companies listed in the Malaysia Stock Exchange.</p>
<p>The total population is 825 companies within 13 categories.</p>
<pre><code>Category Population Sample
Construction: 42 10
Consu... | 69,552 |
<p>Suppose I have 2 exclusive events, and at each point in time, I maintain the probability for the first event, p (the other one being 1-p). There is online, streaming information arriving all the time, and I would like to update p with respect to this new, arriving information. This is an industry, practical problem ... | 69,553 |
<p>Imagine the goal is sampling from $p(X,Y)$ and X and Y are dependent real-valued random variables, i.e. $p(X|Y)\neq p(X)$. Now the question is how can we apply Metropolis-Hastings algorithm on the problem? Obviously it is not possible any more to apply different proposals for $X$ and $Y$ at each step because of depe... | 69,554 |
<p>Someone brought up in conversation that three of her friends had consecutive birthdays (such as November 10, 11, and 12), and I wanted to figure out how likely that is for any randomly selected three people, assuming that birthdays are randomly distributed and the birthdays of two people in a sample are independent.... | 69,555 |
<p>We asked 60 people to list as many restaurant franchises in Atlanta as they could. The overall list included over 70 restaurants, but we eliminated those that were mentioned by fewer than 10% of the people, leaving us with 45. For these 45, we calculated the proportion of informants who listed the franchise, and w... | 69,556 |
<p>I have to do binary logistic regression with a lot of independent variables. Most of them are binary, but a few of the categorical variables have more than two levels.</p>
<p><strong>What is the best way to deal with such variables?</strong></p>
<p>For example, for a variable with three possible values, I suppose ... | 49,684 |
<p>I have always always understood the diagonal of the ROC plot to represent the performance of a "random" classifier (corresponding to an AUC of 0.5). Is this still the case for highly imbalanced problems? (e.g. 10 positives vs 1000 negatives). </p>
<p>If not, is there any way to estimate the ROC-AUC for a "random" c... | 69,557 |
<p>This sounds like an easy setup, and I'm absolutely sure it's not too complicated to do, but somehow I can't figure out how to approach this.</p>
<p>The setting is as follows : There are 6 treatments with 16 subjects in each treatment. Weight is measured for every subject before and after treatment.</p>
<p>The hypo... | 69,558 |
<p>I work with amino acid sequences and I want to use a self-made model to tell me something about it, lets call it $f(\text{seq})$. Now i want to know the contribution of every position in the sequence onto the model, i.e. my question is what is the importance/effect of amino acid $A$ occuring at position $I$ in the s... | 69,559 |
<p>Say I make histograms H1, H2, H4 ...of the same set of data
with bins 1, 2, 4 ... wide.
Then the bins containing a given $x$ have counts and averages</p>
<pre><code>n1 av1 in H1,
n2 av2 in H2,
n4 av4 in H4 ...
</code></pre>
<p>How should one weight these to estimate data(x) ?<br>
One possibility would be $\Sigma w... | 40,348 |
<p>Why is forecast error (MAPE) much higher when using weekly periodicity vs monthly? I am using exactly the same data for both.</p> | 69,560 |
<p>What are the most common method for estimating populations?
We want to estimate the proportion of population of a country that consume drugs or have a determined disease.</p>
<p>I have read something about "The caPTure- recaPTure model". Is there any other model or method? </p> | 69,561 |
<p>I would like a meaningful and concise explanation for what it means exactly, when someone says, "We built a statistical model of all our images". </p>
<p>I overheard this, (and keep overhearing that phrase), but I am not sure how/what that entails exactly. </p>
<hr>
<p>EDIT: Context:</p>
<p>The problem set here ... | 30,115 |
<p>In what cases would I want to know $\operatorname{E}\left[e^X\right]$? I'm in an introductory probability course and I'm presented with exercises like this often, but I'm wondering when someone would want to know, say the probability density function of a random variable $Y$ for $Y=2X$. When is it important to exp... | 69,562 |
<p>I have walking samples from 20 different people. My aim is to detect which walking samples are from which person. I'm trying to achieve this by extracting "walking cycles" from each person's dataset and train a classifier with these "walking cycles". I extracted all cycles: found every walking cycle in the dataset a... | 69,563 |
<p>On page 72 of <em>Introductory Statistics, A Conceptual Approach Using R</em> (Routledge, 2012), the authors first compute the variance of a sample of size $n$ using:</p>
<p>$$\sigma^2=\dfrac{\sum_{i=1}^n(Y_i-\mu)^2}{n}$$</p>
<p>Then, because they do not know the mean $\mu$ of the population, they replace it with ... | 30,117 |
<p>How to obtain SE for covariates that enter a regression directly and through a interaction term?</p>
<p>Any suggestions of how to interpret the statistical significance of covariate that enters a regression directly and through a interaction term?</p>
<p>The problem, to put is simple, is that there are more than o... | 30,118 |
<p>Wondering what the difference is between rel error (relative error) and xerror (apparent error) in regression trees? </p>
<p>I am using the rpart package and the output returns these metrics cross-validated over the number of splits.</p>
<p>Anyone know the difference between these two quantities or perhaps even t... | 69,564 |
<p>I'm researching a method for sampling uniformly from an $n$-dimensional shape, for which conventional rejection sampling may be too slow. I am generating 1,000 points using each method, and wish to compare the quality of their randomness. The points generated using the new method should be identically distributed to... | 69,565 |
<p>I am trying to run a logistic regression analysis in R using the speedglm package.
The data is CNVs (a type of genetic variant), whether that CNV occurred in a case or control and wether genes in a pathway is hit by the CNV or not (Pathway.hit), and how many genes were hit by the CNV that were not in the pathway (P... | 69,566 |
<p>I want to plot Rayleigh fading mixture. can any one give me help in how i can do this by matlab or R ???</p>
<p>this is the link of Rayleigh fading mixture :</p>
<p><a href="http://en.wikipedia.org/wiki/Rayleigh_mixture_distribution" rel="nofollow">http://en.wikipedia.org/wiki/Rayleigh_mixture_distribution</a></p> | 69,567 |
<p>I have fit a non-linear model with 3 parameters to a data set. </p>
<p>I have a preconceived notion that one of the parameters will be one of 2 values. So I would like to compare 2 fits of the same model using the two theoretical values for the fixed parameter.</p>
<p>Because the 2 fits are not nested and hence DF... | 69,568 |
<p>I have to compare the survival proportion between two treatments. Because of some limitations, I can only take a sample of $n_{1}=5$ animals from treatment 1, and $n_{2}=50$ animals from treatment 2. Both samples come from the same batch so that these two samples can be considered as paired. The survival proportion ... | 69,569 |
<p>I'm doing my master thesis on FDI effect on Chinese wage inequality. I am new to quantitative econometrics so I have no idea if my wage equation is correct.</p>
<p>$$W_{it} = β X_{it} + λ_t + η_i + ε_{it}$$</p>
<p>Where the wage paid by firm $i$ in year $t$ is denoted as $W_{it}$. $X_{it}$ contains a set of contro... | 11,843 |
<p>On both a practical and philosophical level, how should you choose the scope when performing multiple comparisons?</p>
<p>When a study performs 10 tests to check the hypothesis that 10 explanatory variable are predictive for "something" (on the same dataset), the test should obviously be corrected.</p>
<p>What if ... | 69,570 |
<p>I have a data like this:</p>
<pre><code>> table(A,B,C)
, , C = FALSE
B
A FALSE TRUE
FALSE 177 42
TRUE 6 8
, , C = TRUE
B
A FALSE TRUE
FALSE 5 31
TRUE 4 10
</code></pre>
<p>How can I plot this on a single graph, possibly without imposing any hierarchy... | 69,571 |
<p>If I have the following dataset:</p>
<pre><code>rankdata <- read.table( text = " time id rank
1 a 1
1 b 2
2 a 2
2 b 3
2 c 1
... | 37,710 |
<p>I'm using McNemar's test. Basically this question is about best practices when reporting results using McNemar's test.</p>
<p>I want to report the effect size. What is a sensible effect size for McNemar's test? I've seen the odds ratio b/c and the proportions b/(b+c) and c/(b+c) both used in papers. If I say what b... | 69,572 |
<p>For example some common ones are engagement, churn, ARPU. The problem with the metrics I mentioned (besides needen to know more) is that I do not understand clearly how are they measure and what they mean in real life.</p> | 69,573 |
<p>Is there a way to reduce the number of interaction terms in a diff-in-diff model to make the results easier to interpret/present?</p>
<p>Background: I'm trying to run the following diff-in-diff regression:</p>
<p>Y = POST + TREAT + A + B + C + POST*TREAT + POST*A + POST*B + POST*C + TREAT*A + TREAT*B + TREAT*C + A... | 69,574 |
<p>I would like to fit <code>LASSO</code> in the following type of data where there are large number of variables (p > n). My y variable is <code>y</code> and would like to fit rest of variables in <code>myd</code> as x variables. </p>
<pre><code>#random population of 200 subjects with 1000 variables
M <- matrix(r... | 69,575 |
<p>Let $X_n, X, Y$ be random variables such that $X_n + cY \stackrel{d}{\rightarrow} X + cY $ for every positive constant $c$. Prove that $X_n \stackrel{d}{\rightarrow} X$. </p>
<p>I know if only we have joint convergence we can show this by the continuous mapping theorem, but even that is not assumed. Just what am I ... | 30,127 |
<p>I have a monthly time series with an intervention and I would like to quantify the effect of this intervention on the outcome. I realize the series is rather short and the effect is not yet concluded.</p>
<p><strong>The Data</strong></p>
<pre><code> cds<- structure(c(2580L, 2263L, 3679L, 3461L, 3645L, 3716L, 3... | 69,576 |
<p></p>
<p>I have a large dataset with common rating factors, Age, Gender, Geographic Location, etc and all the claims that have occurred within the month along with the premium that has accumulated on that policy for the month. An example that will help clarify what I'm talking is <a href="http://imgur.com/4nF7bbj" r... | 30,129 |
<p>I am writing a research proposal for an undergraduate course. I have been advised to use cluster sampling for this proposal but am not sure how to work out the number of clusters that I will need to present with a questionnaire. There are approximately 134 staff members working in 57 settings. There is a minimum of ... | 69,577 |
<p>Suppose I have N potential drugs, each of which have an unknown effect size(Flat prior). As I devote resources to clinical trials for each drug, the standard error of my estimate for the drug's effect decreases according to sigma/sqrt(n). If I have a fixed budget of the number of participants I can have across studi... | 69,578 |
<p>Let's say I'm using a random forest in a true/false classification problem. </p>
<p>When I produce a score for an observation is it possible to get some sort of metric of variable importance for that particular score?</p>
<p>I'd imagine this would be based on the observation's leaf locations across the ensemble.</... | 69,579 |
<p>I have built a classification model to recognise a class and I have evaluated it on several datasets. The problem is that some of these datasets do not have any true instance of the class in question, and so, the model should ideally recognise zero instances.</p>
<p>If the model has 0 false positives on such a data... | 69,580 |
<p>I have these groups where the values are responses to a 10-point Likert item:</p>
<pre><code>g1 <- c(10,9,10,9,10,8,9)
g2 <- c(4,9,4,9,8,8,8)
g3 <- c(9,7,9,4,8,9,10)
</code></pre>
<p>Therefore I used Kruskal-Wallis to determine any differences between responses in the groups, and the result was:</p>
<pre... | 40,374 |
<p>I heard and read several times of the use of 'binning' methods to estimate the uncertainty and the auto-correlation time of a sample generated by MCMC but I can't find a textbook example of it being explained and applied.</p>
<p>Could anyone share it with me?</p> | 69,581 |
<p>I asked two groups of individuals (80 males and 10 females) fill out a questionnaire asking them their attitude towards a series of political variables. Every individual had to answered a set of 16 statements and tell me whether they agreed or disagreed with the statement presented to them (yes/no answers). </p>
<p... | 40,376 |
<p>I have data from an experiment in which each participant provides a binary response to each presented stimulus, which is either correct (1) or incorrect (0). </p>
<p>There are 4 different stimulus types, and 48 stimuli from each group are presented to each participant. I'd like to compare the accuracy achieved betw... | 30,135 |
<p>We know that a ARMA(p,q) process is weakly stationary, iff there is no root of the characteristic polynomial of its AR part lying on the unit circle. </p>
<p>But what is the necessary and sufficient condition for a ARMA(p,q) process to be ergodic? Any book on that?</p>
<p>by "ergodic", I mean its definition in ter... | 36,190 |
<p>I'm reading <a href="http://inside.mines.edu/~pconstan/docs/constantine-primer.pdf" rel="nofollow"><em>this tutorial</em></a> on Galerkin methods for stochastic partial differential equations, Example 2. In this example, a random field $\alpha(x,\omega)$ has a mean $\bar{\alpha}=10$ and covariance function $C_\alph... | 69,582 |
<p>I am given iid pairs $(X_i, Y_i)$, $i = 1, \ldots, n$ and wish to model the regression function
$$
r(x) = E[Y \mid X = x]
$$
nonparametrically. Suppose I have prior knowledge that the relationship between $X$ and $Y$ is primarily a linear one, but possibly deviating from a linear relationship by an unknown function... | 69,583 |
<p>I have some data having structure as like below</p>
<pre><code>[group] [subj] [a score] [pearson correlation1] [pearson correlation2] .... [pearson correlationN]
group1 subject1
group1 subject2
group1 subject3
group2 subject4
group2 subject5
group2 subject6
</code></pre>
<p>And, want to know which [pearson... | 69,584 |
<p>Lets say two groups are compared. Subjects are randomly assigned to each group, then a treatment is given to half while a placebo is given to the other half. All aspects of the experiment (order of treatment, etc) are also randomized. The treatment group gets a much higher "score" than the placebo group on average, ... | 69,585 |
<p>So I need to select my hyperparameters and also my features. A full grid search of the space of hyperparameters and features is too computationally intensive, so what I am doing instead is for each fold of K-fold cross validation:</p>
<p>1) Tune hyperparameters using CV on the training set of the fold, using all fe... | 69,586 |
<p>Suppose I have a probability density function for <strong>x</strong></p>
<p>$$ f_n( {\bf x}; \theta) = \exp(n\theta - \sum_{i = 1}^n x_i) * I(\min{{\bf x}} \ge \theta) $$</p>
<p>Where I is an indicator function ( = 1 if the condition inside the brackets is satisfied, 0 otherwise).</p>
<p>I wish to find the maximu... | 69,587 |
<p>I'd like to do some analysis of shooting efficiency in basketball when a team is leading (AHEAD) or trailing (BEHIND) by less than 8 points and whether they are HOME or AWAY. Here are a few examples of the data:</p>
<pre><code>Ray Allen HOME BEHIND 59.4% 134
Ray Allen HOME AHEAD 57.13% 132
Ray Allen... | 69,588 |
<p>I'm a beginner in data mining and trying to select best classifiers for a dataset. I have no vision about methods of selecting the best classifiers, but I read somewhere about stable and non-stable data and proper classifiers for them.</p>
<p>My main question is that "Is there any algorithm or even any scale to fin... | 69,589 |
<p>I am having trouble figuring out how to create entries for missing dates in my time-series data. I'm trying to use proc expand and I'm able to get entries for dates between the already existing dates shown, but I need to get entries for all quarters between 2003 and 2014. Here is a sample of my problem with SAS code... | 69,590 |
<p>I am doing a regression analysis where several of my independent variables are categorical measures of severity. I code them as dummies and exclude the least severe variable. The more severe the category the lower the dependent variable with y always equal (or nearly equal) to zero when the most severe category is i... | 69,591 |
<p>the conditional mutual between three sets of mutually exclusive variables, X, Y, and Z, is defined as follows.</p>
<p>$I(X,Y|Z) = \sum_{xyz} P(x,y,z) \log \frac{P(z)P(x,y,z)}{P(x,z)P(y,z)}$</p>
<p>my questions concern the $\log$ of the ratio of the probability products. </p>
<ol>
<li>if $P(z)$ or $P(x,y,z)$ is 0,... | 69,592 |
<p>I have a question about a regression I'm running with R. It is on a dataset of 25,000 patients, the regression is about their probability of having a complication. I want to make a prediction of this probability with the estimators of my regression, but I want a prediction-vector with only a select number of patient... | 69,593 |
<p>I am trying to remove seasonality from data. I tried the non-linear trend using the code: trend=lm(NH3cH6~t+cos.t+sin.t). The plot was shown as following:
<img src="http://i.stack.imgur.com/iY6JM.jpg" alt="The dots are the data, the red line is the trend"></p>
<p>However, as you can see, the second peak of the tren... | 69,594 |
<p>Consider the following linear regressions on two sets of data x and y (of same length)</p>
<ul>
<li>y=ax</li>
<li>x=by</li>
</ul>
<p>As you know, the usual optimisation by OLS is usually not giving (at all!) b=1/a</p>
<p>This is because the optimisation algorithm is not symmetric.</p>
<p>My question: is there co... | 69,595 |
<p>I want to compare the results of two items by age category and do not really know what test to use. I tried a <a href="https://en.wikipedia.org/wiki/Cochran%E2%80%93Mantel%E2%80%93Haenszel_statistics" rel="nofollow">Cochran–Mantel–Haenzel–test</a> at first, but I don't think it is testing what I really want to know.... | 30,147 |
<p>I'm having a problem with a factorial design in Minitab, as it is not as clear how to proceed as all problems I've had thus far.</p>
<p>The problem is to create a factorial design with two factors where the first factor, Environment, which has two levels - H2O and Salt H2O whose values overlap (i.e. they cannot be ... | 69,596 |
<p>What are the available methods/implementation in R/Python to discard/select unimportant/important features in data? My data does not have labels (unsupervised).</p>
<p>The data has ~100 features with mixed types. Some are numeric while others are binary (0/1).</p> | 69,597 |
<p>I have run a general linear model which includes 3 scale IVs and 2 categorical IVs and 1 scale DV. I am testing the assumptions of regression and I a not sure how to test multicollinearity since I have categorical variables. I would usually use Pearson correlation between the IVs and test the VIF in a linear regress... | 69,598 |
<p>I have regressed data for rainfall on years 1990-2010. This was a simple linear regression in R using the <code>lm()</code> function. The data represent mean yearly amount of rainfall in mm. When I plotted the residuals, however, I noticed that they follow exactly the same pattern and grouping as my data. </p>
<p>I... | 69,599 |
<p>I have a multivariate Gaussian parameterised by a mean vector $\mu$ and a precision matrix $\Sigma$. Now, I want to set the Gaussian along a given dimension $i$ to a point mass i.e. I set the corresponding diagonal entry i.e. $\Sigma_{ii}$ to infinity (zero variance) and also set all the entries in the ith row and c... | 69,600 |
<p>I am interested in estimating a break point in response to one explanatory variable, while also including other variables as terms in the linear model. One reason to include additional terms is to account for spatial dependency/autocorrelation. The following code was adapted from code provided by @jbowman <a href="h... | 69,601 |
<p>When follow-up is assumed to be constant and variable, is there any relationship between median follow-up and median survival? I.e. should one be less or greater than the other?</p> | 69,602 |
<p>I have a simple question. If I have a small number of observations of a large number of variables, is it the distribution of the variables that matters for a statistical test or the distribution of observations for each variable. </p>
<p>For example if I ask 6 people in two groups (3 people per group) 2,000 questio... | 69,603 |
<p>I am trying to implement Holt-Winters exponential smoothing in Java program (I understand that R and Python have implementations of these algorithms, but I can't use those due to other reasons, so they are ruled out).</p>
<p>I have been going through <a href="https://www.otexts.org/fpp/7/5" rel="nofollow">Rob J. Hy... | 69,604 |
<p>I just had a question as to how to identify the degree of correlation of the random effects in a mixed effects model using R's lme4 package. </p>
<p>I'm investigating a mixed model using lme4, which has the instructions to specify an option in the model specification as to whether the random effects of the model a... | 69,605 |
<p>I have a DB with multiple missing values (scale, ordinal and nominal). I used multiple imputation to fill in these missing values.</p>
<p>How can I perform a repeated measures ANOVA on these (5) datasets? Should I pool them first? And how (or can) I run a repeated measures ANOVA straight away with these 5 (MI) data... | 69,606 |
<p>I am generating a river reach population estimate for a freshwater mussel by summing point estimates made across a gridded point network (within the reach) using a generalized linear mixed model framework. I have generated 95% confidence/prediction intervals at each of the ~150,000 point locations in R. I have summe... | 69,607 |
<p>I am looking at the relationship between an environmental exposure and a health outcome. Measurements have been taken on subjects at a number of different time points and I am trying to work out if the dose-response relationship changes over time. </p>
<p>The outcome is binary variable (0 and 1), and the exposure i... | 40,222 |
<p>I compared Chinese and German websites and found that 20 out of 30 use the same design. So I got a probability of 2/3, right? </p>
<p>Is there a way to find out if that probability is statistically significant? Or is all that I can say that there is a 2 out of 3 chance that the design is the same?</p> | 5,833 |
<p>This is also a question that relates very much to <a href="http://stats.stackexchange.com/questions/1595/python-as-a-statistics-workbench">Python as a statistics workbench</a> and <a href="http://stats.stackexchange.com/questions/3392/excel-as-a-statistics-workbench">excel as a statistics workbench</a>. I know there... | 30,158 |
<p>How does using 1 - correlation as the distance influence the determination of the number of clusters when doing kmeans?
Is it still valid to use the classical indices (Dunn, Davies-Bouldin...)?</p> | 69,608 |
<p>I am using <code>package::roxygen2</code> to develop a package with RStudio. Below is are the roxygen comments to one of my functions, called <code>coltrain()</code>.</p>
<pre><code>#' Collect raw training data using external SQL queries.
#'
#' @details This is a wrapper for the \code{get_data} function.
#' It ... | 69,609 |
<p>I've got a situation where I'd like to evaluate a function of a fitted model, and account for the uncertainty in the fitted model. For example, say I want to calculate the minimum of the function $f(.)$, but I can only get $\hat f(.)$, because I don't know the true function. I got $\hat f(.)$ from a linear model, ... | 69,610 |
<p>I have 5 columns of data in an Excel spreadsheet. </p>
<p>Each row has either 1 or 0 (on or off) within each column. </p>
<p>I'm trying to determine the most common grouping or clustering of columns that have a 1. For example, it could be columns B & D are the most common grouping that have 1s, followed by col... | 69,611 |
<p>I have two sample sets that consist of independent trials of a binomial variable <code>X = {X0, X1}</code>. For the remainder, I denote the probabilities as <code>p0= p(X=X0)</code> and <code>p1= p(X=X1)</code>; the sample sizes as <code>N1</code> and <code>N2</code> and the binomial coefficients as <code>C1</code> ... | 69,612 |
<p>For a list of some hundreds participiants where some measure belongs to each participant, if I sample two groups of size n randomly, I want an algorithm that determines <strong>at which sample size</strong> a t-test or such would yield that the samples are not significantly different (e.g. by comparing the means) - ... | 69,613 |
<p>A signal processing technique, the <a href="http://en.wikipedia.org/wiki/Mel_Frequency_Cepstral_Coefficients" rel="nofollow">Mel frequency Cepstrum</a>, is often used to extract information from a musical piece for use in a machine learning task. This method gives a short-term power spectrum, and the coefficients a... | 40,408 |
<p>I was looking at the <a href="http://en.wikipedia.org/wiki/Fiducial_inference" rel="nofollow">Fiducial Inference</a> page on wikipedia, which is an alternative to the traditional Frequentist and Bayesian standpoints. Although it was out of favour in mainstream statistics for many years, there seems to have been a re... | 69,614 |
<p>After playing way too much Angry Birds, I started to observe my own strategies. It turns out that I developed a very specific approach to getting 3 stars on each level.</p>
<p>That made me wonder about the challenges of developing a machine learning system that would be able to play Angry Birds. Interacting with th... | 40,410 |
<p>Why are the squares of the vertical distances taken rather than the
absolute values?</p> | 49,295 |
<p>A limitations of standard neural net algorithms (like backprop) is that you have to make a design decision of how many hidden layers and neurons-per-layer you want. Usually, the learning rate and generalization is highly sensitive to these choices. This has been the reason, why neural net algorithms like <a href="ht... | 69,615 |
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