Cells with Small Expected Frequencies
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Minitab displays the number of cells that have expected frequencies less than 5. In Example of Chi-Square, there were 2 such cells. Some statisticians hesitate to use the chi-square test if more than 20% of the cells have expected frequencies below five, especially if the p-value is small and these cells give a large contribution to the total chi-square value. If some cells have small expected frequencies, consider combining or omitting row and/or column categories.