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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Frequency and hypothesis

which does it means? the results were processed using frequency tables of data obtained and expected data with a confidence level of 90% and with 4 degrees of freedom. To test the hypotheses, the chi-...
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Power / sample size estimation for chi-square test with continuity correction in R

1._Some authors mention that they estimate sample size for chi-square test with continuity correction. For instance: Sample-size calculation is based on Pearson's Chi-square test with a two-sided ...
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Chi square for three categorical variables

Can I use chi square test with three variables ? The variables are organizational climate (11 dimensions), job satisfaction (7 dimensions) and customer satisfaction (5 dimensions). Likert scale. any ...
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Why does the fact that I estimated my parameters change the way I should use chi−sqaured test?

Suppose I have a data sample and I want to test whether normal distribution with mean $0$ and variance $1$ fits this data sample. If I understand the chi-squared test correctly, I think that I should ...
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When is it appropriate to rescale probabilities when doing a Chi-Square Goodness of Fit Test?

Suppose I have a vector of independent but non-mutually exclusive probabilities (e.g. both x and y can occur at the same time). ...
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How to calculate the statistical significance of the difference in a categorical value of two populations?

There has recently been a statistical report regarding whether Cypriots are ready for a female president. There was a difference in the opinions of men and women and I'm wondering if it is ...
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Sample size study not reflecting findings in R simulation

I have a binomial response variable (a sort of conversion rate for a search mechanism) and just one independent variable, which is the "type" of the search bar template. To illustrate, my ...
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How do I combine two groups into one for Fisher's Exact test?

I'm fairly new to statistics and I need some help. I just ran a survey on colour terms in different languages. I had 3 groups with an unequal number of participants in each: English (27), Scottish ...
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Validating random variable generation from inverse transform sampling

I'm building a simulator and I have to implement some probability distributions. What is the best (formal) way of validating this implementation? I took a look at KS-tests but it seems to me they are ...
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Can the chi-square statistic in Kruskal-Wallis test be compared to determine the most appropriate to distinguish the groups?

I have a dataframe in R which format is similar as follows: v1 v2 v3 group 1 3.5 100 a 3 5 200 a 10 5.5 150 b 8 7.5 210 b 4 4.5 300 c 9 2.5 200 c ... My ...
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How to interpret pvalue for Chi² goodness-of-fit test for Poisson distribution

I'm a bit confused about the pvalues I'd get when checking my own data against a theoretical Poisson distribution. Following e.g. this post here: https://stats.stackexchange.com/a/78175/66544 I'd ...
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References: t-test and Chi-squared test can be conducted with unequal sample sizes

I have two independent groups: sample size of group 1 is 24000, and sample size of group 2 is 246. With the drastically different sample sizes in the two group, I need to use the Student’s t-test or ...
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How to correct Chi-square's p-value when working with very unbalanced contingency tables?

I'm studying the association between a rare disease and smoking. Because the disease is rare, my contingency table is highly unbalanced with way more Non-Diseased than Diseased individuals, ...
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Chi-squared approximation may be incorrect

Please I need your help. I am trying to run this data using R but it throws an error message 'Chi-squared approximation may be incorrect.' Is something wrong with my data? ...
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Chi square fit, fitting data to a straight line: Incomplete gamma function as goodness-of-fit estimation

On page 661 of the book "Numerical Recipes in C:The art of scientific computing", we fit a set of N data points $(x_{i}, y_i)$ to a straight line model $$y(x)=a+bx.$$ We do this by ...
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Confused about interpretation and intuition behind Mcnemar's Test [duplicate]

I've always been under the impression that Mcnemar's Test is for paired categorical data, just like paired t-tests are for paired continuous data. However, I was looking at the Wikipedia article for ...
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How are effect sizes calculated following a cellwise residual analysis?

I have used SPSS to create a 2X4 contingency table concerning the relationship between two categorical variables: depression diagnosis and 4 sleep disruptions. I carried out a chi square test of ...
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I'm not sure how to look at two frequency counts, measured each year for three different years

A friend has asked me to help them analyse some data. They have the following table of data: The table shows the total data for each year in a single hospital, not a sample. The final row is year to ...
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Why is the chi-squared test statistic the accepted measure of distance for goodness-of-fit tests?

I understand the chi-squared test statistic to be a measure of "distance" from the expected distribution. So, for example, suppose I have a 3-sided (fair) die with sides x1, x2, x3. I roll ...
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Reproduce chi-square p-value via simulation

I have a 3-sided (fair) die with sides x1, x2, x3. I roll the die 3000 times and tally the results: x1 * 990, x2 * 1050, x3 * 960. A quick chi-square test reveals that the probability of getting this ...
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what formula does python statsmodels library uses to compute the bp_stat value (the Q value for the Box Pierce test)

As far as I know, the $Q$ statistics is computed with the formula $Q = N \sum_{j=1}^K \rho_j^2 $ I created an example where I compute $Q$ by hand and by using:\ ...
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Goodness of fit for multinomials with small np

I've got a model with continuous explanatory variable $x_i$ and some positive integer $m_i$ for each datapoint, and then a multinomial response - i.e. $p$ categories, and the sum of counts across the $...
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Don't understand why SelectKBest with Chi Square does not involve p-value

According to SelectKBest's documentation page, it 'select features according to the k highest scores', which in this case would be the Chi Square score. https://scikit-learn.org/stable/modules/...
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How should I calculate effect sizes for a 2X4 table?

I have used the software SPSS to produce a 2X4 contingency table, using categorical data. I am aware that odds ratio is only applicable for 2X2 tables. Are there alternatives to odds ratio to try and ...
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R statistical test for two groups with three categorial variables [duplicate]

I have two groups, in which three possible outcomes appeared at different frequencies, and I wanna know, if there is a significant difference in-between the groups. For instance, I have two potatoe ...
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Using Cramér's V to evaluate correlation between categorial variables with small numbers within contingency tables

I am evaluating correlations between categorical variables in a data set. I have seen Cramér's V is one way I can calculate this, and I know it takes the chi-squared statistic as one of the elements ...
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Choosing statistical test for Preference-shift

I am having trouble choosing the proper method to support my hypothesis. I have conducted an animal study, where subjects chose A or B, 6 times a day for 3 days (day 1~3). At first, I divided the ...
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Using a z-test for proportion in place of Chi-Square

Here's the study: Pam knows from prior research that children who are seated in a room with 4 doors are equally likely to pick any door when asked which door they would choose then leaving the room. ...
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Convert a Variable based on a Chi Square Function

I have a variable Average Days Between Purchase (ADBP) on the x-axis for a given customer. Based on this variable I wish to score my customer, but the relationship between the score and the variable ...
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How do I do discriminant validity

How do I do discriminant validity the same as in this paper Page #333 "A Technological Pedagogical Content Knowledge (TPACK) Scale for Geography Teachers in Senior High School" https://www....
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What is the difference between constrained and unconstrained models

I have a question what is the difference between constrained and unconstrained model or freely estimated model. I am trying to test for chi square difference between them to determine discriminant ...
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Discriminant Validity - Chi Square Test

To check discriminant validity between two constructs for CFA in AMOS, I am using chi square difference test to confirm discriminant validity which "can be assessed for two estimated constructs ...
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Extension of Pearson's chi-squared test to sequences of multinomial random variables

Background Suppose we observe $n$ IID Bernoulli variables and our null hypothesis is that their common probability is $p$. For denote by $\mathbb{1}_{\{i\}}$ the outcome of observation $i$. Then by ...
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Are these cases independent?

I have the results of a survey I ran on a sample of fans of a certain game franchise. The franchise has three series, which we'll call, A, B, and C. I asked the respondents to rate their enjoyment of ...
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Chi square test of independence and CI

Can you calculate confidence intervals when performing a chi square test of independence. Someone asked me to provide CI but I'm not sure how this is possible since the test only tests for indepedence....
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How to estimate the statistical significance test duration based on the test results

I'm using a chi-square test to calculate the statistical significance of an A/B test experiment on my website. I found this calculator which can show the duration in days required to achieve ...
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Hypothesis testing for ordinal proportions for multiple independent subjects divided between two groups

I have two biological groups - each with multiple subjects (7 in one and 10 in another). Each subject provides 40-80 observations, which can be classified into either of two ordinal categories. I have ...
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Can we use Pearson chi-squared test when we have only estimated values of parameters?

In our mathematical statistics course we've learnt about Pearson chi-squared test. Our lecturer told us that when we want to test a hypothesis about the distribution (parameters of which can only be ...
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Straightforward question regarding contingency tables

So say I have a 4x4 contingency table. The question I have been asked only concerns the first column. I've been asked to essentially conduct multiple comparisons between each pair of categories ...
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Which statistical test to compare frequencies across groups?

I am running an analysis in which I want identify if there are significant differences in the features that make up two groups: people that commit crimes against children and people that commit crimes ...
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How to test for a statistically significant difference between 3 groups?

MY PROBLEM: I need to test for statistical significance between the three groups. The problem comes when extremely large numbers are involved and the chi-square test is always significant. I read ...
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$\chi^2$ test to determine whether different observations come from the same quantity

Three experiments are performed to measure the same quantity $T$. The three results are $$ \begin{cases} T_A = 990\pm 3\\ T_B = 920\pm 30\\ T_C = 950\pm 12 \end{cases} $$ Using a $\chi^2$ test, and ...
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Correlation between binary variables

Long story short - I am lost among the ways to check for relation (whether there is any) between binary variables. Context - I am working on a side project where I try to analyze marketplace data and ...
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Test whether two categorical questions are statistically different?

I have two questions (Q1, Q2) and they can be answered with either Yes or No. I want to test if there is a significant difference between the answers to Q1 and Q2, because the questions are related to ...
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Power analysis of different statistical test techniques

With reference to this answer which states that chi square test is less powerful compared to other statistical techniques. Can someone shed some light on power analysis of different techniques like Z ...
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Chi square test and Benford's law

I have read that Chi square test is not correct technique for Benford's distribution. Also, the chi-square test applies when both variables are categorical. I am little confused if any or both of ...
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P-value of chi-square test of independence

I need help understanding chi2 independence test scipy.stats.chi2_contingency. Let's assume I have two samples (of different sizes) of a categorical variable with 3 possible outcomes (1, 2, 3): Counts ...
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Confidence intervals for Poissonian statistic

According to Cash 1979, which makes use of the C-statistic: $C=-2\times ln\,L_{Poisson} + const$ (where $L_{Poisson}$ is the Poissonian likelihood), the application of the Wilks theorem allows to use ...
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Identify outliers in chi-squared goodness of fit test

I am performing a chi-square goodness of fit test to compare an observed value with an expected value. The expected value is calculated from theory. p-value suggests statistical significance. How do I ...
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Sampled vs population relative frequency distribution

Assume I have a real count of people by city, and I have 4 cities, A,B,C,D (for simplicity), and the people distribute 30%, 30%, 25%, 15% respectively. I also have a sample of this population, which ...
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