Answer
(a) 0.1539
(b) 0. 4276
(c) 0.0202
(d) (c) is unusual because it is less than 0.05
Work Step by Step
Using a graphing calculator:
(a) normalcdf(0, 15, 21.3, 6.2) = 0.1539
(b) normalcdf(18, 25, 21.3, 6.2) = 0.4276
(c) normalcdf(34, 100, 21.3, 6.2) = 0.0202
(d) answer given above