Question

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 be 99% confident that the estimated (sample) proportion is within 5 percentage points of the true population proportion of customers who are males?

z0.10	z0.05	z0.04	z0.025	z0.01	z0.005
1.282	1.645	1.751	1.960	2.326	2.576

Use the table of values above.

Answer 1

We have given,                  
Preliminary estimate for proportion not given therefore, consider=0.5                  
Margin of error =E=0.05
Level of significance =1-0.99=0.01
Z critical value is (by using Z table) =2.576
Sample size formula is                   

Sample size =664