Answer: 68
Step-by-step explanation:
As per given , we have
Margin of error : E= 0.10
Critical z-value for 90% confidence interval : [tex]z_{\alpha/2}=1.645[/tex]
Since , the estimate of true proportion is unknown , then
The formula to find the sample size :-
[tex]n=0.25(\dfrac{z_{\alpha/2}}{E})^2\\\\ n=0.25(\dfrac{1.645}{0.10})^2\\\\ n=67.650625\approx68[/tex]
The required minimum sample size= 68