The ages of members of an Olympic water polo team are: 22, 25, 23, 28, 29, 21, 20, 26.
a. Calculate the mean and population standard deviation for this group.
b. The same team members are chosen to play in the next Olympic Games 4 years later. Calculate the mean and population standard deviation of their ages at the next Olympic Games.
c. Comment on your results in general terms.