What is the difference between a chi square test of independence and a chi square test for homogeneity?
chi square test of independence helps us to find whether 2 or more attributes are associated or not.e.g. whether playing chess helps boost the child's math or not. It is not a measure of the degree of relationship between the attributes. it only tells us whether two principles of classification are significantly related or not, without reference to any assumptions concerning the form of relationship.
chi square test of homogeneity is an extension of chi square test of independence...tests of homogeneity are useful to determine whether 2 or more independent random samples are drawn from the same population or from different populations. instead of one sample- as we use with independence problem, here we have two or more samples.
Both the types of tests are concerned with cross classified data. both use the same testing statistics. However they are different from each other.
Test for independence is concerned with whether one attribute is independent of the other and involves a single sample from the population.
On the other hand, test of homogeneity tests whether different samples come from same population. It involves 2 or more independent samples-one from each of the populations in question.