Answer:
(a) Margin of error ( E) = $2,000 , n = 54
(b) Margin of error ( E) = $1,000 , n = 216
(c) Margin of error ( E) = $500 , n= 864
Step-by-step explanation:
Given -
Standard deviation
= $7,500
= 1 - confidence interval = 1 - .95 = .05
=
= 1.96
let sample size is n
(a) Margin of error ( E) = $2,000
Margin of error ( E) = 
E = 
Squaring both side


n = 54.0225
n = 54 ( approximately)
(b) Margin of error ( E) = $1,000
E = 
1000 = 
Squaring both side


n = 216
(c) Margin of error ( E) = $500
E = 
500 = 
Squaring both side


n = 864