Answer:
Then solution as long as n ≥ 56
Step-by-step explanation:
The Normal distribution will provide a good approximation to evaluate proportion tests when the following conditions are met:
n*pâ‚€ > 10
n*qâ‚€ > 10
As  p₀ = 0,82    q₀ = 0,18    n  = 13    30   56   and  100
We test:
A) n = 13 Â Â Â Â n*qâ‚€ Â = Â 13*0,18 = 2,34 Â Â Â 2,34 < 10 Â
B) n = 30 Â Â Â n*qâ‚€ Â = Â 30*0,18 = 5,4 Â Â Â Â 5,4 < 10
C) n = 56 Â Â Â n*qâ‚€ Â = Â 56 * 0,18 = 10,08
           n*p₀  = 56 * 0,82 = 45,92
D) n = 100 Â Â Â n*qâ‚€ Â = 18
           n*p₀  = 82
If we test 55  we find that  55*0,18  =  9,9
Then solution as long as n ≥ 56