Two pain-relieving drugs were compared for effectiveness on the basis of length of time elapsing between administration of the drug and cessation of pain. Thirteen patients received drug 1, and 13 received drug 2.

The sample variances were s2 1 ¼ 64 and s2 2 ¼ 16.

Test the null hypothesis that the two populations variances are equal. Let a ¼ :05.