# Question: Several retired bicycle racers are coaching a large group of

Several retired bicycle racers are coaching a large group of young prospects. They randomly select seven of their riders to take part in a test of the effectiveness of a new dietary supplement that is supposed to increase strength and stamina. Each of the seven riders does a time trial on the same course. Then they all take the dietary supplement for 4 weeks. All other aspects of their training program remain as they were prior to the time trial. At the end of the 4 weeks, these riders do another time trial on the same course. The times (in minutes) recorded by each rider for these trials before and after the 4-week period are shown in the following table.

a. Construct a 99% confidence interval for the mean d of the population paired differences, where a paired difference is equal to the time taken before the dietary supplement minus the time taken after the dietary supplement.

b. Test at a 2.5% significance level whether taking this dietary supplement results in faster times in the time trials.

Assume that the population of paired differences is (approximately) normally distributed.

a. Construct a 99% confidence interval for the mean d of the population paired differences, where a paired difference is equal to the time taken before the dietary supplement minus the time taken after the dietary supplement.

b. Test at a 2.5% significance level whether taking this dietary supplement results in faster times in the time trials.

Assume that the population of paired differences is (approximately) normally distributed.

## Answer to relevant Questions

One type of experiment that might be performed by an exercise physiologist is as follows: Each person in a random sample is tested in a weight room to determine the heaviest weight with which he or she can perform an incline ...Refer to the information given in Exercise 10.4. Test at a 1% significance level if the two population means are different. n1 = 650 1 = 1.05 σ1 = 5.22 n2 = 675 2 = 1.54 σ1 = 6.80 A sample of 500 observations taken from the first population gave x1 = 305. Another sample of 600 observations taken from the second population gave x2 = 348. a. Find the point estimate of p1 – p2. b. Make a 97% confidence ...The lottery commissioner’s office in a state wanted to find if the percentages of men and women who play the lottery often are different. A sample of 500 men taken by the commissioner’s office showed that 160 of them ...Two local post offices are interested in knowing the average number of Christmas cards that are mailed out from the towns that they serve. A random sample of 80 households from Town A showed that they mailed an average of ...Post your question