3. (Part 5 of 6) (Mission 11) (Skull Breadths) The summary of maximum breadths of samples of male Egyptian skulls from 4000 B.C. and 150 A.D. is provided below.

4001 B.C. : sample size=25, sample mean: 128, sample standard deviation: 5

150 A.D.: sample size=16, sample mean: 132, sample standard deviation: 8

(3-a) Construct a 90% confidence interval for the difference in the sizes of skulls.

(3-a-4) The lower bound for the confidence interval is

Group of answer choices

-9.760

None listed

-7.920

-8.383