The degenerative disease osteoarthritis most frequently affects weight-bearing joints such as the knee. The following is a summary of data on stance duration (ms) for samples of both older and younger adults. Assume that both stance duration distributions are Normal.
Age Sample Size Sample Mean Sample SD
Older 28 801 117
Younger 16 780 72
a. Calculate and interpret a 99% CI for true average stance duration among elderly individuals.
b. Carry out a test of hypotheses at significance level 0.05 to decide whether true average stance duration is larger among elderly individuals than younger individuals.