Answer: 601
Step-by-step explanation:
When the prior estimate of population proportion is not given , the formula we apply to find sample size :
, where z* = critical z-value
E=Margin of error
Given : Margin of error = 0.04
Confidence level = 95%
We know that , according to the z-table , the critical value for 95% confidence interval = z*= 1.960
Then, the required sample size :
Hence, the required minimum sample size = 601