11. A consumer advocacy group is concerned about the va riab ility in the cost o f prescription medication. The group surveys e ig h t local pharmacies and obtains the fo llow in g prices fo r a particular brand o f medication:

$25.50 32.00 33.50 28.75 29.50 35.00 27.00 29.00

a. Calculate th e po in t e s t ima t e o f th e pop u la t ion variance.

b. The g r ou p a s sum e s th a t th e a b o v e prices r epre sent a r andom samp le drawn from a normal ly d is tributed populat ion. Cons truct a 90% interval e s t ima te o f th e pop ula t ion variance.

c. The g r ou p d e c id e s to be g in a lobb y ing ef fort on its mem b e r s 'b e h a l f if th e variance in th e price d o e s not equal 4. What sh ou ld th e g r ou p do?