Answer: 896
Step-by-step explanation:
Given The prior estimate of proportion of the population stay informed on local issues through the radio: [tex]p=0.3[/tex]
Margin of error : [tex]E=0.03[/tex]
Significance level : [tex]\alpha: 1-0.95=0.05[/tex]
Critical value : [tex]z_{\alpha/2}=1.96[/tex]
The formula to find the sample size :-
[tex]n=p(1-p)(\dfrac{z_{\alpha/2}}{E})^2\\\\ n=(0.3)(0.7)(\dfrac{1.96}{0.03})^2=896.373333333\approx896[/tex]
Hence, the necessary sample size is at least 896 .