From a random sample of 68 businesses, it is found that the mean time that employees spend on personal issues each week is 4.9 hours with a standard deviation of 0.35 hours. What is the 95% confidence interval for the amount of time spent on personal issues?

(4.71, 5.09)

(4.83, 4.97)

(4.55, 5.25)

(4.82, 4.98)

If a confidence interval is given from 8.52 to 10.23 and the mean is known to be 9.375, what is the margin of error?

8.520

0.855

1.710

0.428

If the population standard deviation of a increases without other changes, what is most likely to happen to the confidence interval?

narrows

cannot determine

does not change

widens

From a random sample of 41 teens, it is found that on average they spend 31.8 hours each week online with a population standard deviation of 5.91 hours. What is the 90% confidence interval for the amount of time they spend online each week?

(29.99, 33.61)

(30.28, 33.32)

(25.89, 37.71)

(30.62, 32.99)

A company making refrigerators strives for the internal temperature to have a mean of 37.5 degrees with a population standard deviation of 0.6 degrees, based on samples of 100. A sample of 100 refrigerators have an average temperature of 37.70 degrees. Are the refrigerators within the 90% confidence interval?

Yes, the temperature is within the confidence interval of (37.40, 37.60)

No, the temperature is outside the confidence interval of (36.90, 38.10)

Yes, the temperature is within the confidence interval of (36.90, 38.10)

No, the temperature is outside the confidence interval of (37.40, 37.60)