Four research teams each used a different method to collect data on how

fast a new brand of paint dries. Assume that they all agree on the sample size

and the sample mean (in minutes). Use the confidence level; confidence

interval) pairs below to select the team that has the smallest sample

standard deviation.

O

A. Confidence Level: 99.7%; Confidence Interval: 42 to 48

B. Confidence Level: 95%; Confidence Interval: 40 to 50

O

C. Confidence Level: 95%; Confidence Interval: 35 to 55

D. Confidence Level: 68%; Confidence Interval: 44.5 to 45.5

Option D.

Step-by-step explanation:

Recall that the wider the confidence interval, the greater the variability.

In other words, wider confidence interval will have bigger sample standard deviation.

For option A, the width is |48-42|=6

For option B, the width is |50-40|=10

For option C, the width is |55-35|=20

For option D, the width is |45.5-44.5|=1

Therefore the team in option D has the smallest sample standard deviation.

As for the confidence level, it is just telling us the extent to which we confidence that, the parameter is within the interval

Answer: D