Degrees of Freedom In Exercise 20 “Blanking Out on Tests,” using the “smaller of n1 - 1 and n2 - 1” for the number of degrees of freedom results in df = 15.

Find the number of degrees of freedom using Formula 9-1. In general, how are hypothesis tests and confidence intervals affected by using Formula 9-1 instead of the “smaller of n1 - 1 and n2 - 1”?