an owner of a miniature golf course wants to know how many strokes it takes to get the ball in the last…

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?\nusing a sample of size 30\nusing a sample of size 75\nconstructing a 95% confidence interval\nconstructing a 99% confidence interval

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?\nusing a sample of size 30\nusing a sample of size 75\nconstructing a 95% confidence interval\nconstructing a 99% confidence interval

Answer

Explanation:

Step1: Recall margin - of - error formula

The margin of error $E = z\cdot\frac{\sigma}{\sqrt{n}}$ for a confidence interval of the mean (when population standard - deviation $\sigma$ is known), where $z$ is the z - score corresponding to the confidence level, $\sigma$ is the population standard deviation, and $n$ is the sample size.

Step2: Analyze the effect of sample size

The margin of error is inversely proportional to the square root of the sample size $n$. That is, as $n$ increases, $E$ decreases. When we go from $n = 40$ to $n = 30$, the sample size decreases, and the margin of error will increase. When we go from $n = 40$ to $n = 75$, the sample size increases, and the margin of error will decrease.

Step3: Analyze the effect of confidence level

The z - score $z$ increases as the confidence level increases. For a 90% confidence interval, the z - score $z_{90}$ is smaller than the z - score $z_{95}$ for a 95% confidence interval, and $z_{95}$ is smaller than the z - score $z_{99}$ for a 99% confidence interval. As the confidence level increases, the z - score increases, and the margin of error increases. So, constructing a 95% or 99% confidence interval will increase the margin of error compared to a 90% confidence interval.

Answer:

using a sample of size 75