In Exercise 72, we saw that the towns in the region south of Derby seemed to have fewer deaths than the towns in the north. To see whether that difference is statistically significant, look at this histogram of 1000 differences in mean Mortality by Region. What does it say about whether a difference of 242.7 is statistically significant?

Data From Exercise 72

Recall from Chapter 7, Exercise 75,  that data were collected on the annual mortality rate (deaths  per 100,000) for males in 61 large towns in England and  Wales. In addition, the water hardness was recorded as the  calcium concentration (parts per million, ppm) in the drinking  water. The data set also notes, for each town, whether it was  south or north of Derby. Is there a significant difference in  mortality rates in the two regions? Here are the summary  statistics.

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Summary of: mortality For categories in: Region Group Count Mean Median StdDev 1631.59 1631 138,470 North 34 South 27 1388.85 1369 151.114 Mortality 2000 1800 1600 1400 1200 North South Region