Ginkgo for Dementia The herb ginkgo biloba is commonly used as a treatment to prevent dementia. In a study of the effectiveness of this treatment, 1545 elderly subjects were given ginkgo and 1524 elderly subjects were given a placebo. Among those in the ginkgo
treatment group, 246 later developed dementia, and among those in the placebo group, 277 later developed dementia. We want to
use a 0.01 significance level to test the claim that ginkgo is effective in preventing dementia. Test the claim using a hypothesis test.
Given test Statistic z = -1.66
Write Hypothesis and Critical Value, do you Support or reject the claim.