Suggested answer to exercise: Analyses for qualitative data, 4

Question 4: What method could we use to test the null hypothesis that the two classifications are related, and why?

Suggested answer

The expected values here must all be small, as all four of them must sum to 8. Hence we cannot use a chi-squared tests, but must use Fisher’s exact test. This is not significant, P = 0.067. The invalid chi-squared test would give chi-squared = 6.00, df = 1, P = 0.014. This would be very misleading.

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Last updated: 27 July, 2009.

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