Question

The campus bookstore reported that students paid an average of $255 per semester for textbooks. To verify this statement, the student union decided to select a random sample of students and found the following amounts, in dollars, spent for textbooks: $252 $289 $298 $266 $254 $261 $275 $263 $268 $315 $251 $266 $320 At the 0.10 significance level, can we conclude that the average amount spent on textbooks per semester has increased? a. What is the decision rule? (Round the final answer to 3 decimal places.) Reject H0: µ ≤ 255 and accept H1: µ > 255 when the test statistic is 1.356 . b. What is the value of the test statistic? (Round the final answer to 3 decimal places.) Value of the test statistic = 3.147 c. What is your decision regarding H0? H0. There is evidence to conclude that the mean number rate of return is higher than 255.

d. What is the p-value? p-value i need p value.

Answer 1

a)

This is right tailed test, for α = 0.1 and df = 12
Critical value of t is 1.356.
Hence reject H0 if t > 1.356

b)

Test statistic,
t = (xbar - mu)/(s/sqrt(n))
t = (275.2308 - 255)/(23.1774/sqrt(13))
t = 3.147

c)

reject the null hypothesis.

d)

P-value = 0.0042