Question

question 11 of 25
a 90% confidence interval for a proportion is found to be (0.22, 0.28). what is
the sample proportion?
a. 0.26
b. 0.24
c. 0.28
d. 0.25

Explanation:

Step1: Recall the formula for the confidence interval of a proportion

The confidence interval for a proportion is given by $\hat{p}-E

Step2: Calculate the mid - point

The formula for the mid - point of an interval $(a,b)$ is $\frac{a + b}{2}$. Here, $a = 0.22$ and $b=0.28$. So, $\hat{p}=\frac{0.22 + 0.28}{2}$.

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Answer:

D. 0.25