Suppose the manager of a shoe store wants to determine the current percentage of customers who are males. How many customers should the manager survey in order to be80%

confident that the estimated (sample) proportion is within3

percentage points of the true population proportion of customers who are males?

z

0.10

z

0.05

z

0.04

z

0.025

z

0.01

z

0.005

1.282

1.645

1.751

1.960

2.326

2.576