An owner of a miniature golf course wants to know how many strokes it takes to get the ball in the last hole. The owner randomly selects 40 golfers and asks them how many strokes it took them. The owner then constructs a 90% confidence interval for the true mean number of strokes to get the ball in the hole. Which of the following would decrease the margin of error?

The margin of error gets smaller when the sample size increases, because a larger sample gives a more precise estimate of the true mean. Increasing the sample from 40 to 75 golfers would decrease the margin of error. A sample of 30 would increase it, and raising the confidence level to 95% or 99% would require a wider interval.

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