In a sample of 8 high school students, they spent an average of 28.8 hours each week doing sports with a sample standard deviation of 3.2 hours.

In a sample of 8 high school students, they spent an average of 28.8 hours each week doing sports with a sample standard deviation of 3.2 hours. Find the 95% confidence interval, assuming the times are normally distributed.

(26.12, 31.48)

(22.47, 35.21)

(25.62, 32.48)

(24.10, 34.50)

In a sample of 15 stuffed animals, you find that they weigh an average of 8.56 ounces with a sample standard deviation of 0.07 ounces. Find the 92% confidence interval, assuming the times are normally distributed.

(8.543, 8.577)

(8.528, 8.591)

(8.526, 8.594)

(8.521, 8.599)

Market research indicates that a new product has the potential to make the company an additional $3.8 million, with a standard deviation of $1.7 million. If this estimate was based on a sample of 10 customers from a normally distributed data set, what would be the 90% confidence interval?

(3.06, 4.54)

 (2.81, 4.79)

(2.76, 4.84)

(2.11, 5.56)