Statistical Analysis Stack Exchange
Statistical Analysis Stack Exchange

Questions tagged [chi-squared-test]

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

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Chi-squared test with 0 expected values

My contingency table: heterozygous homozygous.minor homozygous.major observed 2 0 3 expected 0 0 5 The expected population is composed of only AA genotype, but in the…
crysis405
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What is the definition of expected counts in chi square tests?

Just wondering whether anyone could define expected counts in regards to a chi square test.
Joanna
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Chi squared for goodnes of fit test always rejects my fits

I am using lmfit to fit a function in Python. This is my fit: Log scale: Lin scale: where the histogram is my data and the dashed line the fit. The error bars are simply the sqrt of the number of counts. I would like to decide on whether it is a…
user171780
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When is the maximum value of chi square achieved for a non-symmetric table?

Let us say we have an RxC table, when R and C are not necessarily equal, when is the maximum value of the Chi Square statistic achieved? and how can this be proven?
Tal Galili
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What is the maximum for Pearson's chi square statistic?

I actually know that the answer is $N(k-1)$ (where $k$ is the minimum between number of rows and number of columns). However, I can not seem to find a simple proof for why the statistic is bounded by this. Any suggestions (or references?)
Tal Galili
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Choice of grouping in Chi-Squared test

Let's say I have a categorical variable. I try to test the null hypothesis that each category has the same count (of something) using a Pearson's Chi-Squared test. I may not be able to reject null hypothesis using just the categorical variables,…
T.J. Gaffney
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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 with the substance in different concentrations. I…
user2487380
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Can you use the chi-squared test when the expected values are not determined?

I have six ratios (females-males). These are the observed values: 1.78 - 1.17 - 0.53 - 1 - 0.85 - 0.56 I need to run a chi-squared test to show that these ratios are significantly different. I expect all these ratios to be equal. But as for the…
Gwen
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Chi square test when sample sizes are different?

I have two samples from two different language corpora: Sample one contains 82 verbs, sample 2 contains 89 verbs. I want to compare the frequencies of a particular verb type, let's call them oral verbs, across both samples and see if they differ…
Soles
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Chi-squared test: Investigating fruit flies attraction to different colours

I have a few questions about the Chi-squared test. First of all, this is what I was investigating: H0: Fruit flies show no difference in attraction to light of different colours Protocol: 20 fruit flies put in tube. Tube is marked into 3 equal…
user123587
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Chi Square for this case?

I am not sure how to perform the statistical analysis on the following table. I did an experiment in which 12 participants had to choose between 3 conditions when provided with 3 stimuli. Stimulus Condition1 Condition2 Condition 3 A …
L_T
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Testing the likelihood that two percentages are equal

I'm looking for a method to determine the likelihood that two percentages from independent groups are EQUAL. In this case I'm looking at the likelihood of symptom improvement from patients gathered through two different methods (one traditional…
JudoWill
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How does chi-squared test of homogeneity differ from other chi-squared tests?

I am familiar with the chi-squared goodness of fit test and also the chi-squared test of independence. An example of the chi-squared goodness of fit is where we have frequencies for three different groups and want to know if the observed proportions…
luciano
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ZINB vs binomial model goodness of fit testing

I have read that the Vuong test is no longer considered appropriate for testing whether a ZINB fits better than a negative binomial test because it is not strictly non-nested nor partially non-nested. I'm modeling in R (glmmTMB) and there is not the…
Claire Richards
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Where do chi squared p-value lookup tables come from?

I'm doing a lot of labs in science and my teacher always wants us to find the chi-squared values of our data and find the probability of that occurring from a lookup table. Where do these probabilities come from in the lookup table? Is there a…
whackamadoodle3000
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