The mean and the standard deviation of the sample of 40 trash bag breaking strengths are and = 50.575 and s = 1.6438.
a. What does the histogram in Figure 2.17 say about whether the Empirical Rule should be used to describe the trash bag breaking strengths?
b. Use the Empirical Rule to calculate estimates of tolerance intervals containing 68.26 percent, 95.44 percent, and 99.73 percent of all possible trash bag breaking strengths.
c. Does the estimate of a tolerance interval containing 99.73 percent of all breaking strengths provide evidence that almost any bag a customer might purchase will have a breaking strength that exceeds 45 pounds? Explain your answer.
d. How do the percentages of the 40 breaking strengths in Table 1.9 that actually fall into the intervals [± s], [± 2s], and [± 3s] compare to those given by the Empirical Rule? Do these comparisons indicate that the statistical inferences you made in parts b and c are reasonably valid?
Figure 2.17

Table 1.9

Transcribed Image Text:

Histogram of Breaking Strengths 30 25 20 15 10 25.0 20.0 20.0 10.0 10.0 7.5 2.5 25 2.5 Strength (in lbs) TABLE 1.9 Trash Bag Breaking Strengths Ф TrashBag 48.5 52.3 53.5 50.5 50.3 49.6 51.0 48.3 50.6 50.2 52.5 47.5 50.9 49.8 50.0 50.8 53.0 50.9 49.9 50.1 50.7 48.2 51.5 49.0 51.7 53.2 51.1 52.6 51.2 49.5 49.4 51.9 52.0 48.8 46.8 51.3 49.3 54.0 49.2 51.4