5. A sample of 25 statistics students had an average test score of 82.1 and standard deviation of 6.4. Use this information to construct a 98% confidence interval estimate of the population standard deviation. Round your final answer to one decimal place.

6. A train company claims the average speed at 4pm on a particular freeway is faster than 62mph. When ten vehicles were observed at random for their speeds (in mph) on a particular stretch of freeway, the following data was obtained: 68, 78, 69, 61, 68, 65, 60, 64, 60, 62. Assume vehicle speed is normally distributed.

a. State the hypotheses and identify the claim.

b. Calculate the test statistic and p-value.

c. State your conclusion based on the =. 05 significance level. What does this say about the train company's claim?