Chapter 12.1, Problem 18E

For Exercises 7 through 20, assume that all variables are normally distributed, that the samples are independent, that the population variances are equal, and that the samples are simple random samples, one front each of the populations. Also, for each exercise, perform the following steps.

a. State the hypotheses and identify the claim.

b. Find the critical value.

c. Compute the test value.

d. Make the decision.

e. Summarize the results, and explain where the differences in the means are.

Use the traditional method of hypothesis testing unless otherwise specified.

18. Calories hi Fast-Food Sandwiches Three popular fast-food restaurant franchises specializing in burgers were surveyed to find out the number of calories in their frequently ordered sandwiches. At the 0.05 level of significance, can it be concluded that a difference in mean number of calories per burger exists? (The information in this exercise will be used for Exercise 7 in Section 12-2.)

FF#1	FF#2	FF#3
970	1010	740
880	970	540
840	920	510
710	850 820	510

Source: www.fatcalories.com