Answer: 78
Step-by-step explanation:
The formula use to find the sample size is given by :-
[tex]n=(\dfrac{z_{\alpha/2}\ \sigma}{E})^2[/tex]
Given : Margin of error : [tex]E=\pm\$2,000[/tex]
Standard deviation : [tex]\sigma=\$9,000[/tex]
Significance level : [tex]\alpha=1-0.95=0.05[/tex]
Critical value : [tex]z_{\alpha/2}=1.96[/tex]
The formula use to find the sample size is given by :-
[tex]n=(\dfrac{(1.96)\ (9000)}{2000})^2=77.7924\approx78[/tex]
