Question: The herbal supplement ginkgo biloba is advertised as producing and increase in physical strength and stamina. To test this claim, a sample of n = 31 adults is obtained and each person is instructed to take the regular daily dose of 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 µ=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 α=.05?

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