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

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251 views

Why are these two random variables identically distributed?

Let $(X_1, X_2, \ldots, X_i, \ldots, X_k)$ be $k$ independent, normally distributed random variables with means $\mu_i$ and variances $1$. Then the random variable $$ \sum_{i=1}^k X_i^2$$ is ...
0
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1answer
13 views

Survey data: finding the most significant predictors?

I have about 5,000 responses to a survey in which users were asked how strongly they agreed with a statement on a 5-point Likert scale. This response is my dependent variable - I want to find out what ...
2
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1answer
17 views

Dependent chi-squares vector: how to calculate cdf of $X_{(n)}$?

Consider a vector of central&1-degree Chi square distributed variable $(X_1, X_2,...,X_n)$, it is simple to calculate the cdf of $X_{(n)}$ (maximum of order statistics), when they are independent. ...
2
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1answer
62 views

chi-squared test when variables dependent

For a square matrix, is it appropriate to use a chi-squared distribution when each level of the variables are assumed to have the same overall frequency? Specifically, I'm analyzing a dataset of the ...
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0answers
37 views

chisq.test with R

I want to do a Goodness-of-Fit test of my data and the Weibull-distribution. I have estimated the Weibull distribution using the survreg-function in R. Now I want ...
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0answers
20 views

Chi-squared test and logistic regression

Is there a relation between chi-squared test and logistic regression model in a similar manner between ANOVA and linear regression?
2
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1answer
20 views

Chi-Squared Goodness of Fit Test Alternative? - Zero Can't Be in Denominator

I have 5 zones(categories) in which a certain percentage of total sinkholes exist. I have 5 different maps that I am testing to see which one provides me with the best fit to my expected percentages ...
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0answers
5 views

About Chi Square Statistic Table [closed]

I do not understand relation with The Chi Square Statistic table based on the link above. Why and how can it be "2.706" och "3.841"? I understand why it will be Df 1 but ot for the column 0.10 ...
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28 views

Is the chi squared test appropriate?

I have claim data from two different insurance administrators. From each administrator, I have calculated the relativity of miles driven per year based on claim data. I want to determine whether ...
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1answer
8 views

What's the right test to use to find significance in a table of incidence rates?

I have some data about conversion rates on different browsers, as follows. ...
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0answers
18 views

$\chi^2$ test vs F-test in feature selection

In the context of feature selection for classification, does it make sense to use one filter based on $\chi^2$ test and the other one based on F-test? Or they are "interchangeable"?
2
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1answer
39 views

stats for 2x4 contingency table with both very large and small or zero counts

I have 7000 2x4 contingency tables with count data. They represent a particular position in a genome and the number of times each dna nucleotide is observed at that position in 2 different ...
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0answers
11 views

Chi-Square analysis after ANOVA and correlations failed to give results

I have a continuous dependent variable and two independent grouping variables of age and gender. Age has three groups and gender two (obviously!). Now ANOVA has shown no differences across both. ...
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1answer
27 views

Please help me interpret this goodness of fit test

In the game of Bridge, 52 cards are distrubuted randomly among 4 players, each player ending up with 13 cards. I implemented a random number generator using the RNGCryptoServiceProvider form the ...
0
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2answers
17 views

Calculating chi-squared values for percentages?

I'm using scipy and I'd like to calculate the chi-squared value of a contingency table of percentages. This is my table, it's of relapse rates. I'd like to know if there are values that are ...
2
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0answers
23 views

Visualise significant differences in a contingency table?

I'm working with pandas and scipy, and I would like to find a quick way to visualise unusual values in a contingency table. Say this is my contingency table: ...
0
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2answers
34 views

Logistic regression, Chi-square, and study design

I have a study in which I have developed a new predictor (binary) for a disease (also a binary variable). The study has two parts. In the first part, I want to test if my predictor is strongly ...
2
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1answer
28 views

Can we run a chi squared test on a normalized function?

Hi I am fit a maxwell distribution and attempt to find the chi squared value in two cases: When the data is normalized. When the data is un-normalized. My problem is that the two ...
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0answers
4 views

post-hoc multiple comparisons with chi squared using spss v. 22

I am carrying out an analysis using a 4$\times$2 crosstab. I found an overall significant difference but I would like to find if there are significant differences among the 4 groups. Is there a way ...
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2answers
18 views

Chi-square test for Homogeneity problem (cell count less than 2)

My table of chi-square test for homogeneity has 3x5 cells, 3 samples to a likert scale item. Most cells in the table have a frequency count of less than two, so it is recommended to discard the column ...
3
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2answers
129 views

Confidence Interval on a random quantity?

Suppose $\vec{a}$ is an unknown $p$-vector, and one observes $\vec{b} \sim \mathcal{N}\left(\vec{a}, \frac{1}{n} I\right)$. (For example, the sample mean based on $n$ observations of i.i.d. normal ...
2
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0answers
25 views

Chi-squared calculation for (nonlinear) model goodness of fit for data with trials

I would like to be certain of how to calculate the $\chi^2$ value for this scenario: We desire a measure of the goodness of fit of a nonlinear model to a data set. The data consists of many ...
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1answer
60 views

Using chi goodness of fit to test if data comes from normal distribution

The problem gives 50 observations and then asks to check whether the data comes from a normal distribution. For instance if these are your observations then how would you go about testing to see if ...
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0answers
20 views

What statistical test to use for A/B testing

I'm trying to understand how A/B testing works for a simple 2x2 contingency table. I have found two different types of solutions: 1) Calculate an aggregate probability of conversion assuming that ...
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0answers
22 views

Pairwise chi-squared tests with Bonferroni correction

I have two categorical datasets, say, $A$ and $B$, which are sparse. I would like to apply pairwise $\chi^2$ tests to a certain categories, which are sufficiently populated (say, have expected values ...
3
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1answer
57 views

Pearson's $\chi^{2}$ value?

Pearson's $\chi^{2}$ value is 115.778 and 4 cells (33.33%) have expected count has less than 5. I am confused how to interpret this output. I have a 2 by 6 contingency table. Can someone tell me what ...
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28 views

To get the overall significant p value, am I on the right track for LMM?

According to this document: http://www.bodowinter.com/tutorial/bw_LME_tutorial2.pdf I can get the overall p-value of fix effects by comparing models that I would like to know to null model. In my ...
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2answers
59 views

Test identicality of discrete distribution

Is there a standard way to test whether two vectors were drawn with the same discrete distribution in R? Something like a Kolmogorov-Smirnov test, but for discrete distributions. I think two-sample ...
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0answers
28 views

How to test for a home bias in a data set?

I'm trying to think how I can test a data set I have, for transactions between buyers and sellers, for a home bias. My hypothesis is that buyers would rather buy from a merchant from their home ...
0
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1answer
22 views

Chi square test of association

I wanted to study the distribution of BMI by age. So I randomly made age groups and did a chi square test. Is this appropriate?
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3answers
90 views

I do not have hypotheses for my research and I have got only categorical data. what kind of data analysis can i conduct? also

I do not have hypotheses for my research and I have got only categorical data. what kind of data analysis can i conduct for correlation between variables? also is chi-square used only for hypotheses ...
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0answers
23 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 ...
5
votes
1answer
96 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
42 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 ...
3
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1answer
37 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
27 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
17 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: ...
0
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1answer
46 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 ...
2
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1answer
54 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 ...
2
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1answer
46 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 ...
4
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2answers
83 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
11 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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0answers
17 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, ...
0
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0answers
38 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
32 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 ...
0
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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: ...
0
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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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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 ...