The average annual cost (including tuition, room, board, books and fees) to attend a public college takes nearly a third of the annual income of a typical family with college-age children (Money, April 2012). At private colleges, the average annual cost is equal to about 60% of the typical family's income. The following random samples show the annual cost of attending private and public colleges. Data are in thousands of dollars.

Private Public

52.8 20.3

43.2 22.0

45.0 28.2

33.3 15.6

44.0 24.1

30.6 28.5

45.8 22.8

37.8 25.8

50.5 18.5

42.0 25.6

14.4

21.8

a.Compute the sample mean and sample standard deviation for private and public colleges. Round your answers to two decimal places.

x1=

S1=

x2=

S2=

b.What is the point estimate of the difference between the two population means? Round your answer to one decimal place.

Interpret this value in terms of the annual cost of attending private and public colleges.

$

c.Develop a 95% confidence interval of the difference between the annual cost of attending private and pubic colleges. Round your answer to hundreds. Usettable.

From 95% confidence interval, private colleges have a population mean annual cost $to $which is more expensive than public colleges.