Chi | Chi-square degree of freedom
StatisticalhypothesistestAchi-squaredtest(alsochi-squareorχ2test)isastatisticalhypothesistestusedintheanalysisofcontingencytableswhenthesamplesizesarelarge.Insimplerterms,thistestisprimarilyusedtoexaminewhethertwocategoricalvariables(twodimensionsofthecontingencytable)areindependentininfluencingtheteststatistic(valueswithinthetable).[1]Thetestisvalidwhentheteststatisticischi-squareddistributedunderthenullhypothesis,specificallyPearsonschi-squaredtestandvariantsthereof.Pearsonschi-squaredtest...
Statistical hypothesis test
A chi-squared test (also chi-square or χ2 test) is a statistical hypothesis test used in the analysis of contingency tables when the sample sizes are large. In simpler terms, this test is primarily used to examine whether two categorical variables (two dimensions of the contingency table) are independent in influencing the test statistic (values within the table).[1] The test is valid when the test statistic is chi-squared distributed under the null hypothesis, specifically Pearsons chi-squared test and variants thereof. Pearsons chi-squared test is used to determine whether there is a statistically significant difference between the expected frequencies and the observed frequencies in one or more categories of a contingency table. For contingency tables with smaller sample sizes, a Fishers exact test is used instead.
In the standard applications of this test, the observations are classified into mutually exclusive classes. If the null h...