**9. Correct. ****The answer is true**

Using the following confidence interval formula for large populations (n ≥ 30):

Probability (X
+/- z_{c} sn^{-1/2})
= 95%

Where X = 0.85

z_{c} = 1.96

s = 0.05

n = 50

Upper limit =
0.85 + 1.96*0.05* 50^{-1/2} = 0.865 or 86.5%

Lower limit =
0.85 - 1.96*0.05* 50^{-1/2} = 0.836 or 83.6%