Question

question 9 of 10
a 90% confidence interval is found to be (32,48). what is the margin of error?
a. 16
b. 14.4
c. 8
d. 7.2

Explanation:

Step1: Find the sample mean

The sample mean $\bar{x}$ is the midpoint of the confidence interval.
$$\bar{x}=\frac{32 + 48}{2}=\frac{80}{2}=40$$

Step2: Calculate the margin of error

The margin of error $E$ is the distance from the sample mean to either end of the confidence interval.
$$E=48 - 40=8$$

Answer:

C. 8