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 day. 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?

α= .05? (Assume that the herb is expected to increase scores.)