A sample of n = 64 college students yielded on average IQ score of x=121.5 withs =18. (a) Find a 95% confidence interval for µ for the population from which these students were selected, assuming the...

A sample of n = 64 college students yielded on average IQ score

of x=121.5 withs =18.

(a) Find a 95% confidence interval for µ for the population

from which these students were selected, assuming the population standard deviation is a =15.

(b) Find a 95% confidence interval as in part (a) assuming a is

unknown.

(c) Find a 99% confidence interval as in part (b).