A random sample of the price of gasoline from 40 gas stations in a region gives the statistics below. Complete partsa) throughc).

y=$4.19, s=$0.22

a) Find a 95% confidence interval for the mean price of regular gasoline in that region.

( , )

(Round to three decimal places asneeded.)

b) Find the90% confidence interval for the mean.

( , )

(Round to three decimal places asneeded.)

c) If we had the same statistics from a sample of 60 stations, what would the95% confidence interval benow?

( , )

(Round to three decimal places asneeded.)