Question

3 multiple choice 1 point the police chief of a town is trying to determine the average speed of drivers on a specific road. - the police chief took a random sample of the speeds of 100 drivers on the road. - the mean was 48.5 miles per hour, with a standard deviation of 2.5 miles per hour. - the police chief wanted to decrease the margin of error of his next sample. which choice would decrease the margin of error? (note: margin of error ≈ 2·(s/√n), where s is the standard deviation and n is the sample size.) - changing the time that the data is collected - changing the road on which the data is collected - increasing the sample size - decreasing the sample size clear my selection

Explanation:

Step1: Recall Margin of Error Formula

The margin of error is given by \( \text{Margin of Error} \approx 2\frac{s}{\sqrt{n}} \), where \( s \) is the standard deviation and \( n \) is the sample size.

Step2: Analyze Each Option

• Changing the time or road: These do not affect \( s \) or \( n \) in the formula, so they won't change the margin of error.
• Increasing sample size (\( n \)): Since \( n \) is in the denominator under a square root, increasing \( n \) will decrease \( \frac{s}{\sqrt{n}} \), thus decreasing the margin of error.
• Decreasing sample size: This would increase \( \frac{s}{\sqrt{n}} \), increasing the margin of error.

Answer:

Increasing the sample size