Answer: 141
Step-by-step explanation:
Let p be the population proportion of adults over 50 never graduated from high school.
As per given , we have
Prior estimate of proportion for adults with 5 to 30 age graduated from high school group : p= 0.25
Significance level : [tex]\alpha: 1-0.90=0.10[/tex]
Critical z-value : [tex]z_{\alpha/2}=1.645[/tex]
Margin of error : E= 0.06
Sample size will be :-
[tex]n=p(1-p)(\dfrac{z_{\alpha/2}}{E})^2\\\\=0.25(1-0.25)(\dfrac{1.645}{0.06})^2[/tex]
Simplify ,
[tex]n=140.938802083\approx141[/tex]
Hence, the required sample size younger age group be surveyed = 141
