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...

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. those in the ginkgo group, 246 later developed dementia, and among those in the placebo group, 277 later developed dementia ( based on data from " Ginkgo Biloba for Prevention of Dementia," by DeKosky et al., Journal of the American Medical Association, Vol. 300No. 19). We want to use a 0.01 significance level to test the claim that ginkgo is effective in preventing dementia.