In a survey of 2480 golfers, 15% said they were left-handed. The surveyʹs margin of error was 3%. Construct a confidence interval for the proportion of left-handed golfers.

Question

Quizplus · Accepted Answer

To construct the confidence interval, we first need to find the standard error of the proportion: sqrt(0.15 * 0.85 / 2480) = 0.009. Then, using a 3% margin of error, our z-score is 1.96. So the confidence interval is 0.15 ± 1.96(0.009), which simplifies to (0.12, 0.18). Therefore, the best choice is A.

In a Survey of 2480 Golfers, 15% Said They Were