Question: . The herbal supplement ginkgo biloba is advertised as producing an increase in physical strength and stamina. To test this claim, a sample of n=36 adults is obtained and each person is instructed to take the regular daily dose of the herb for a period of 30 days. At the end of the 30-day period, each person is tested on a standard treadmill task for which the average, age-adjusted score is u=15. The individuals in the sample produce a mean score of M=16.9 with SS=1260.

a. are these data sufficient to conclude that the herb has a statistically significant effect using a two-tailed test with a =.05?

b. what decision would be made if the researcher used a one-tailed test with a=.05? (assume that the herb is expected to increase scores.)