Question

A mail order company has a 12% success rate. If it mails advertisements to 542 people, find the probability of getting less than 58 sales. Round z-value calculations to 2 decimal places and final answer to at least 4 decimal places.

Answer 1

P (x < 58 )

n= 542

p = 12%= 0.12

q = 1 - 0.12 = 0.88

542*0.12 = 65.04

Mean= n p = 542 (0.12) = 65.04

Standard Dev= √(n*p* q)= √( 542 * 0.12 * 0.88 )= 7.57

z = 57.5 - M / SD = 57.5 - 65.04 / 7.57 = -0996

Using z score table = 0.15962

probability of getting less than 58 sales = 0.15962