2
QuizMultiple Choice

Introduction to Confidence Intervals

Question 2 • CA-Statistics and Probability B

A clinic measured the systolic blood pressure for a random sample of 10 patients. The resulting 95% confidence interval for the mean systolic blood pressure of all the patients at this clinic was (111.3, 129.5). What was the margin of error for this confidence interval?

Answer
A
9.1
B
18.2
C
120.4
D
240.8

Explanation

The margin of error is half the width of the confidence interval. Its width is 129.5 − 111.3 = 18.2, so the margin of error is 18.2 ÷ 2 = 9.1. Therefore, the correct choice is A, 9.1.

AI-written and checked against the verified answer.

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