5.

This is the same as problem 4, except z = 1.96

a = u - zσ = 2370 - 1.96(375) = 1635

b = u + zσ = 2370 + 1.96(375) = 3105

6.

For this problem, the area between u and b is 90% - 50 = 40%. Therefore, z = 1.29 (see

problem 4) and b = 70 + 1.29 (5) = 53.75. Reference: Frame 71.)

7.

Same as problem 6, except the area between u and b is 951 - 50% = 45%. Therefore, z =

1.65 (.4500 or table between .4495 and .4505) and b = 70 + 1.65 (5) = 88.75.

(Reference: Frame 71.)