# Questions tagged [chi-squared-test]

A test (typically of distribution, independence, or goodness of fit), for the family of distributions use [chi-squared-distribution].

2,456 questions
Filter by
Sorted by
Tagged with
598 views

### Can the χ² test be used without a contingency table?

I thought that the chi squared (χ²) test is to be used when one has an r × c contingency matrix, i.e., when the dependent variables are nonnegative, span the same <...
• 645
37 views

### Statistical Analysis for Physics Research Project [closed]

Important concepts for Problem: $\chi^2$ test, $p$-value, $\sigma$ Significance I am an undergraduate Physics student working on a research project which involves a certain level of statistical ...
38 views

### Weird results from Chi Square test

I'm running a chi square test on some categorical values pertaining to race, and whether different racial groups participated in a clinic. As there's about a dozen different races in this data, I ...
21 views

• 11
1 vote
66 views

### Why are ztest and chisquared test not returning equivalent sample size results?

I'm using the statistical software G*Power to find the minimum sample size needed to detect whether or not the difference in two proportions is statistically significant in an AB test I'm setting up. ...
• 149
1 vote
15 views

### The right test to check whether the two tables are independent from each other [closed]

Table A Group Year 1 Year 2 1 0.4 0.45 2 0.3 0.33 3 0.2 0.6 4 0.1 0.12 5 0.07 0.11 6 0.03 0.06 7 0.01 0.02 Table B Group Year 1 Year 2 1 0.43 0.42 2 0.313 0.39 3 0.223 0.65 4 0.112 0.18 ...
• 11
75 views

### Goodness of fit for exponential model in lmfit

I'm having a dataset where I measured the growth of a given molecule over 7 timepoints. The growth can be described by the formula: $(P_{0} - plateau) * e^{-k t} + plateau$ , where k is the growth ...
• 51
55 views

### How are the confidence interval of Cramer's V and the Chi square statistic related?

I wondered about the relationship between a confidence interval for Cramer's V (I used the rcompanion package and the command cramerV(table, ci = TRUE)) and the result of the chi-squared test (I used ...
70 views

### SPSS, how to properly interpret adjusted residuals in crosstabs with chi-squares larger than 2x2?

I would greatly appreaciate an easy to understand answer. To my understanding if the adjusted residual is +/- 1.96 or more (or less if negative) then something is going on. What exactly does the ...
• 103
1 vote
31 views

### chi square, greek or roman?

I would like to report a chi square statistic evaluated from an experimental population in a manuscript. Do I use (1) the lower case Greek letter ($\chi^2$), (2) the upper case Greek letter ($X^2$), ...
• 13
51 views

### Is it possible to do a contrast in a 2x2 (or more) contingency table or am I completely missing the point?

I have the following 2x2 contingency table of observed frequencies: ...
• 101
1 vote
14 views

### If in the Fisher's exact test, one did not condition on the margin totals, how would the margin totals be factored in the calulation?

It states in the following post What does the assumption of the Fisher test that "The row and column totals should be fixed" mean? that: Fisher's exact test conditions on the margin totals, ...
• 2,315
18 views

### What is the implication of conditioning on the margins in the Fisher's Exact Test? [duplicate]

In the following post: Chi-square test or Fisher's Exact test, it was mentioned by Glen_b that You don't have to have fixed margins to use the Fisher exact test, you only need to be willing to ...
• 2,315
48 views

### How to run a post-hoc correction test on multiple chi-square test?

I have run chi-square tests on occurrence of species across two time periods. As I have 1300 species I analysed them in bulk using a multiple loop function in R: chitest1<- t(sapply(seq(nrow(...
46 views

### What is the $\chi^2$ contingency test really showing?

I have a friend who used this function to compute a chi-squared contingency table in a paper they are writing, and I don't think I fully understand what the results of this test are. Function ...
12 views

### Statistic tests in "table 1" - which to choose?

I have made a table overall comparing two cohorts - a "table 1". The table includes gender, age and 2 different scores from the two cohorts. I would like to test if gender, age and the 2 ...
• 1
33 views

### Calculating Critical Value for Mixture of Two Chi-Square Distributions

Let's say I have a statistic X which is distributed as a mixture of two chi-square distributions; $$X \sim 0.5\chi^2_1 + 0.5\chi^2_2.$$ I'm wondering how I can calculate the critical value(and p-value)...
• 249
644 views

### Chi squared test with reasonable sample size results in R warning

I am trying to identify whether a specific sample is likely coming from a certain data population using the chi squared test. I use R to do the calculation and my ...
• 165
12 views

### Chi-Squared Goodness-of-Fit... with Probabilities?

For background, I am working on a sabermetrics project where I predict probabilities of events with Naive Bayes classifiers. I calculate the observed expected-value probability from the test-set ...
21 views

### Quantifying Dependency in Chi Squared Test

I am running a Chi Squared test on nominal values and this is the contingency table. ...
22 views

### Chi squared min / max (as in best / worst possible fit) values

Naturally the answer to the former would be 0 in case of a perfect fit. But how would one go about finding out the value of the worst possible fit? Background: Doing a simple experiment to crack ...
24 views

### how to compare percentages of intervention group before and after interventions? (repeated dependent variable are presented in categorical variables)

I am conducting a randomized controlled trial, and after intervention, the numbers of patients with some characteristics (for example, prediabetes or IGT) have changed. I want to compare the ...
• 21
31 views

### Chi square statistics (chen & thissen, 1997) for local dependence testing in IRT models

I have recently computed the test for local dependence based on X2 statistics (Chen & Thissen, 1997) in RStudio with the mirt package like this: residuals(fit.SKIDDETdisc, type = "LD", ...
• 31
1 vote