Question

Carmela randomly selected 85 stamps from a stamp collection. Eleven of these were commemorative stamps.

What is the interval estimate for the proportion of commemorative stamps in the entire collection if the sampling method had a margin of error of ±0.035 ?
(0.075, 0.145)

(0.285, 0.355)

(0.082, 0.089)

(0.095, 0.165)

Answer 1

The answer is (0.095, 0.165)

Explanation:

I just took the test and got it right

Answer 2

(0.095, 0.165)

Explanation:

Confidence interval :

Phat ± margin of error

Margin of Error = 0.035

Phat = x / n

Phat = 11 / 85 = 0.1294117

Hence,

Phat ± 0.035

Lower boundary = 0.1294117 - 0.035 = 0.0944

Upper boundary = 0.1294117 + 0.035 = 0.1644

(0.0944, 0.1644)