Answer to Question 1
Find x0 such that P(X x0 ) = 0.90 = P(Z z0 ).
Since the area to the left of z0 is greater than 0.5, z0 must be larger than zero such that P(0 < Z < z0 ) = 0.40, so z0 = 1.28. Thus, x0 = 75 + (1.28 )(4 ) = 80.12
Answer to Question 2
FALSE