1) While writing an article on the high cost of college education, a reporter took a random sample of the cost of new textbooks for a semester. The random variable x is the cost of one book. Her sample data can be summarized by the following.

(Give your answers correct to two decimal places.)n = 22, x = 3518.6, and (x - x)² = 9852.4(a) Find the sample mean, x. $ (b) Find the sample standard deviation, s. $ (c) Find the 99% confidence interval to estimate the true mean textbook cost for the semester based on this sample.

Lower Limit	$
Upper Limit	$

2)The addition of a new accelerator is claimed to decrease the drying time of latex paint by more than 4%. Several test samples were conducted with the following percentage decrease in drying time. Assume that the percentage decrease in drying time is normally distributed.

5.2

6.5

3.6

5.8

3.4

2.1

2.8

4.3

(a) Find the 95% confidence interval for the true mean decrease in the drying time based on this sample. (Give your answers correct to two decimal places.) ____________ to _________________

3)A student group maintains that each day, the average student must travel for at least 25 minutes one way to reach college. The college admissions office obtained a random sample of 32 one-way travel times from students. The sample had a mean of 19.3 minutes and a standard deviation of 10 minutes. Does the admissions office have sufficient evidence to reject the students' claim? Use = 0.01.(a) State the appropriate null and alternative hypotheses. H₀: ? = > < 25 H_a: ? = > < 25 Find t. (Round your answer to two decimal places.) Find the p-value. (Round your answer to four decimal places.)

4) Use a computer or calculator to find the p-value for the hypothesis test. (Give your answer correct to three decimal places.)H_o: = 73, H_a: 73, n = 16, x = 71.36, s = 3.6

Use a computer or calculator to find the p-value for the hypothesis test. (Give your answer correct to three decimal places.)H_o: = 32, H_a: > 32, n = 15, x = 33.25, s = 2.6

Calculate the value of t for the hypothesis test. (Give your answer correct to two decimal places.)H_o: = 73, H_a: 73, n = 12, x = 71.12, s = 3.7

Calculate the value of t for the hypothesis test. (Give your answer correct to two decimal places.)H_o: = 32, H_a: > 32, n = 15, x = 32.95, s = 2.9