A test (typically of distribution, independence, or goodness of fit) or a family of distributions related to such a test.

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17 views

Fitting Model with MCMC?

In fitting a model with several variable I have found extremely useful a method involving the minimization of the Chi Square using a MCMC approach. In particular, I followed this tutorial ...
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0answers
16 views

Nested Standard Deviations

This is a finance question but most of it is statistics related. A few years ago the Chicago Board Options Exchange created the volatility index VIX, which is really just the 30-day standard ...
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1answer
57 views

How to statistically compare groups for multiple density plots?

Is there a statistical method to compare these density plots other than ANOVA (MANOVA)? I would like to compare the densities among year within each plot and report which of those distributions are ...
4
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1answer
33 views

Is there a PDF for a generalized non-central chi-squared distribution [duplicate]

Is there a PDF for a distribution defined as a sum of squares of random variables pulled from a family of normal distributions with different standard deviation? Is there a way of analytically ...
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1answer
36 views

How does Pearson's Chi Squared Statistic approximate a Chi Squared Distribution

So if Pearson's Chi Squared Statistic is given for a $1 \times N$ table, then its form is: $$\sum_{i=1}^n\frac{(O_i - E_i)^2}{E_i}$$ Then this approximates $\chi_{n-1}^2$, the Chi-Squared ...
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2answers
20 views

Missing values in SPSS for Chi-Square Tests

I'm a postgraduate student, doing a accent perception study, this is my first time using SPSS! I'm conducting the above tests on my data, where my participants used Likert scales to analyse the ...
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0answers
11 views

How To Determine Association Plot in R and p-value

I have created a contingency table and an association plot in R and I am not quite sure how to interpret it. Here is my contingency table: ...
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1answer
36 views

Conditional or unconditional exact test in R

I have a 2x2 contingency table and i want to calculate if the pair inside is significantly different. i made a matrix like the following named raw_matrix ...
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1answer
44 views

Post hoc $\chi^2$ test with R

This is a quite simple question but I don't find any good, clear, precise answers: I'm looking for a way to perform post hoc test on a chi$^2$ test. I have 2 variables : var1 : good/fair/poor and ...
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1answer
40 views

Correct use of Chi-Square?

I am trying to test whether one group is significantly different from another in two different collections of data. I have seen that people tend to use chi-squared or fisher's exact for this ...
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2answers
75 views

Interplay of Categorical Data

I apologize if my phrasing is un-educated, I don't have much of a stats background. I'm struggling to find info answering my question because I lack the terminology to accurately describe it. Let's ...
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0answers
7 views

chi-squared feature selection

I have a feature vector of size 250 x 35. That is I have 250 images and each image has 35 features in it. I need to do chi-squared test to get the most significant features out of it. anyone know ...
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16 views

how to test if a proportion of alleles is different between conditions?

I am in doubt about which type of test I could performed on my data. I have a data frame of the following type: contig, pos, A1, A2, Ctrl_A1, Ctrl_A2, Treat_A1, Treat_A2 comp1293557_c0_seq1, 284, ...
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27 views

Chi-squared test with scipy: what's the difference between chi2_contingency and chisquare?

I'd like to run a chi-squared test in Python with scipy. I've created code to do this, but I don't know if what I'm doing is right, because the scipy docs are quite sparse. Background first: I have ...
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1answer
31 views

Cooccurence of Two Categorical Variables

I am trying to calculate if there is a dependence between two categorical columns, or a significant cooccurence of two categorical variables. Let's say I have columns A and B, and and out of 200K ...
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0answers
28 views

Web Videos that can provide me with a better understanding of statistical concepts

I have an exam coming up and I would like to know are there youtube videos/playlist or any videos online that can explain the following concepts below in a simple manner. The concepts are: ...
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1answer
13 views

What is the best way to quantify concordance of two tests?

I have two different medical diagnostic tests, both test the same condition (binary outcome). The condition in question is rather vaguely defined, so they don't always agree. What would be the best ...
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1answer
102 views

$t$ test vs $\chi^{2}$ once sample is split into two groups?

I would appreciate some guidance regarding the use of a t test vs $\chi^{2}$. I am looking at some small set of demographic data (n only 13). I have divided up the sample into two sets, those with ...
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0answers
28 views

Best proportions test based on counts (accuracy, distribution, etc)

I'm trying to compare two sets of counts over totals. For example, subject 1A will have 40 out of 600, and subject 1B will have 3 out of 20. How do I compare these proportions and counts while taking ...
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1answer
28 views

What does y argument do in chisq.test in R?

The chisq.test function in R includes a y = argument, which is to NULL by default. The help ...
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1answer
23 views

Is there a significantly different number of people between groups?

How do I estimate whether a given number of people across groups (say, 72 people in group 1, 95 in group 2 and 70 in group 3) significantly differs from a random distribution of people across groups? ...
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1answer
22 views

Appropriate Statistical Test for multiple groups

I have a question regarding which test I should run on some data. I have small groups of people who answered questions. The answers to these questions have been classified as correct or incorrect. ...
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1answer
79 views

Comparing large categorical data sets with low or zero counts

I'm dealing with a biological feature which can be classified into $2^{20}$ categories. I also have two pretty large data sets of 1 and 3 million entries. Actually, only around 30 thousand categories ...
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20 views

How to approximate error on Chi-Squared Fit when bin counts are zero

I am using a galaxy image simulator that provides a 2D histogram that has the number of photons per pixel (bin) $N$. I am currently using a least-squares residual: $\sum_{bin}(f_{data}-f_{model})^2$ ...
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4answers
42 views

Two groups are significantly different? Test to use

I have two groups of discrete data (integers): ...
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1answer
26 views

prop.test: correcting for large number of observations

This is not really a coding question but more of a statistical question. I'm doing a proportions test on multiple proportions for many subjects. For example, subject 1 will have multiple proportions ...
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0answers
47 views

Different p-values between Wald Z and Wald Chisquare

I have used lme4 for mixed effects models of reaction times and accuracy rates. I could not use lmerTest because the type of model I was using are not yet implemented there (problem with predictors ...
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25 views

Overly-sensitive goodness of fit measure: where did I go wrong?

I'm using the chi-squared goodness-of-fit measure to evaluate instances of a fairly complicated model, but the evaluation is unbelievably sensitive to small variations in the model parameter values. ...
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1answer
110 views

chi square test or Z test?

SO I have an outcome from a biological experiment, where I have counted the number of dead cells upon a mutation. For example, in once case - out of 120 cells we saw 16% of the dead cells, but our ...
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1answer
75 views

Proper analyses for 2x2 contingency tables

So I have multiple questions about the different types of analyses that can be used on a 2x2 contingency table and when different analyses should be used. To open, I'll note that this stems from my ...
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2answers
101 views

Combining $\chi^{2}$ tests

I have a problem with statistics. I'm looking at whether variation in the concentration of a certain substance affects how strongly insects are drawn towards it. I did this by baiting insect traps ...
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1answer
24 views

Multiple value Chi Squared test in SPSS

I am currently doing a study into factors that affect mortality in a particular type of bacterial infection. I would like to compare certain patient characteristics. One of which is the specialty ...
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0answers
36 views

Chi-square test for one group

I'm struggling with this problem. 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​​, ...
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0answers
15 views

Chi-squared test where observations can have multiple categories

I am investigating patterns in click-order on images. A user is asked to click on an image in 5 places (can be the same place). This sequence of 5 clicks makes up a graphical password. I am looking ...
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1answer
58 views

Why use chi-square (or other) statistic over regression modeling for 2x2 contingency tables?

I have a question regarding the use of logistic/log-linear regression vs. contingency test statistics, such as chi-square. Can someone explain to me why it would ever be preferable to use test ...
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2answers
74 views

Best way to test for co-occurrence of measures

I have some data with temporal measures over time. I'd like to test whether two binary variables co-occur more often than chance would predict, and I'm wondering the best (simple) way to do that. The ...
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0answers
20 views

Measure of probability of obtaining a certain $\chi^2$ given the number of trials

I am calculating an equation with several random components a large number of times, and in order to select my final answer I choose that with the minimum value for $\chi^2$. I am hoping to find some ...
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0answers
16 views

How to interpret merits in Weka with ChiSquaredAttributeEval and SVMAttributeEval?

I want to interpret the goodness of attributes using feature selection with 10-fold cross validation. With ChiSquared I get something like this (deletet attributes with merrit was 0 in all folds): ...
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7 views

Probability of certain value of $\chi^2$ given a number of trials

I am calculating a result and an associated $\chi^2$ via an iterative process that makes use of 3 random numbers (randomly sampling a Gaussian) in an equation, and I select as my final result the one ...
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3answers
73 views

Understanding $\chi^{2}$ and Cramér's $V$ results

I have two groups of buyers, A and B, and I want to test whether the difference between the percentage of them who would buy a ...
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0answers
20 views

Sampling weight, logistic regression and chi-square analysis [duplicate]

I have some questions. I am doing logistic regression. but my sample is small(n=129). And in DV, the smallest number of cases is 27(1'). Actually, I hope to use 12 predictors. However, I know the rule ...
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1answer
27 views

Which feature selection method to use for classification problem

I have to do some feature selection for a classification problem with numeric features. I am not sure which feature selection method to use. Chisquared test or Spearmann's rank correlation ...
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15 views

Independent Categories with multiple responses, chi-square too simple, MRCV log-linear model too complex?

Hello all and thanks in advance for your consideration, My research question is simple: Do lynx have a different diet in summer compared to winter? Data structure looks simple at first glance, ...
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0answers
10 views

$\chi^2$ goodness of fit - how to compute expected counts when $\exists$ unknown parameters [duplicate]

This isn't my original problem, but I'm posting a simplified version and then I'll try to see if I can apply it myself to my original problem. (yay for self-learning) Suppose I have a sample and I ...
5
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1answer
248 views

Is the beta distribution really better than the normal distribution for testing the difference of two proportions?

I'm working at an online agency, where we run a lot of AB testing in order to test differences in proportion between two groups (test vs. control). Standard practice in the industry for testing ...
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0answers
25 views

How to corretly scale sum of squared residuals of two different sets of data in order to compare them?

I did numerical simulations of two different systems that returned me N=1000 histograms expressed as $\{x,y,y'\}$, where $x$ is the independent variable, $y=P(x)$ is the probability distribution ...
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1answer
33 views

How can I do a chi-square test without being given the critical value table?

I have a random number generator that generate integers within [0, r). I want to write a piece of code to test whether the numbers from it are truly uniformly ...
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0answers
44 views

Combining chi-squared statistics

I have performed a survey in which users click on an image and the position of this click is recorded. I want to see if where a user clicks is independent of an attribute of the user (say gender). ...
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2answers
46 views

Multiple comparison on subgroups and overall comparison

I am trying to work out is there is any association between occurrence or not of an event in around 500 individuals and their randomised binary grouping (intervention vs placebo). However I also want ...
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2answers
53 views

Can Fisher's exact test accept a 'vector of probabilities'?

The R function chisq.test allows a 'vector of probabilities' to be set with the p argument. Is there an equivalent for ...