What makes a chi-square test invalid?
If the expected counts (also called expected frequencies) for the cells are very small, the results of the test may not be valid. If one or more categories have expected counts that are too low, you can combine them with adjacent categories to achieve the minimum required expected count.
What to do if expected value is less than 5?
The conventional rule of thumb is that if all of the expected numbers are greater than 5, it’s acceptable to use the chi-square or G–test; if an expected number is less than 5, you should use an alternative, such as an exact test of goodness-of-fit or a Fisher’s exact test of independence.
What to do when expected count < 5 warning for a chi?
For example, if all your cells have expected higher than 1 and about 80% are above 5, you’re probably safe just treating it as chi-square (in that the p-values will still be roughly correct in instances you’ll care to have good accuracy in). If expecteds are close to equal you can go lower.
What should the chi square value be for a chi square test?
For a Chi-square test, a p-value that is less than or equal to the specified significance level indicates sufficient evidence to conclude that the observed distribution is not the same as the expected distribution. Here, we can conclude that a relationship exists between the given categorical variables. What is a good chi-square value?
What are the assumptions in the chi square test of Independence?
1. Check assumptions and write hypotheses. The assumptions are that the sample is randomly drawn from the population and that all expected values are at least 5 (we will see what expected values are later). H 0: There is not a relationship between the two variables in the population (they are independent)
Can you use chi square on more than two variables?
If we have two categorical variables both of them have 3 levels and the (33.3%) have expected count less than 5, so the result of chi-squared test will not be accurate. What is the alternative test? Alternatives of Fisher’s exact test for more than 2 groups?