The random sample of n 5 100 Americans in Example 9.7 had an average of 3400 mg of sodium per day, with a sample standard deviation of 1100 mg. Does this provide sufficient evidence to indicate that the average daily sodium intake for Americans is more than 3300?

1. Select Stat ➤ Basic Statistics ➤ 1-Sample Z and select Summarized data in the top drop-down list in Figure 9.15(a). Enter the values for n and x in the appropriate boxes and enter the value for s 5 1100 in the box marked “Known standard deviation.” (Notice that we are assuming that the population standard deviation, s , can be approximated by s.)

2. Click the radio button marked “Perform hypothesis test” and enter the value for m0. In the Options dialog box, change the alternative hypothesis from the two-tailed default to a right-tailed alternative. Click OK twice to obtain the output—z =.91 with p-value = 0.182—shown in Figure 9.15(b). The results are not significant.