Answer: 10 customers.
Step-by-step explanation:
The formula to find the required sample size :
(1)
, where p= prior population proportion.
n= sample size.
= Population standard deviation from previous studies.
Let p be prior population proportion of the customers who click on ads on their smartphones .
As per given , we have
p=0.62
E= 0.27
For 92% confidence , significance level :
The critical value of z for 92% confidence interval from z-table would be
Put theses values in the formula (1), we will get
Therefore , the company should survey 10 customers .
