Question

The herb ginkgo biloba is commonly used as a treatment to prevent dementia. In a study of its effectiveness, 1544 elderly subjects were given ginkgo and 1543 elderly subjects were given a placebo. Anong those in the ginkgo group, 250 later developed dementia, and among those in the placebo group, 296 developed dementia. Use a 0.05 significance level to test the claim that ginkgo is effective in preventing dementia. Based on your results, is ginkgo effective in preventing dementia?

TYPE (including your name) the question on a separate page and the solution must fill an entire page. No hand drawn graphs, equations or symbols all must be computer generated and no liquid paste. Everything can be done in Word. Be sure to include the null and alternative, significance level, critical value(s), the test statistic with calculations shown, the properly drawn graph, decision criteria, decision and one of the four possible conclusions. Don't forget to anser the question at the end of the problem.

Answer 1

Lets take a significance level of 5%.

Which means our critical value would be -1.645.

So reject H0, if tstat<-1.645

Hence as t*<-1.645, we reject H0.

Hence we conclude that there is sufficient evidence to conclude that ginkgo is effective in treating dementia.