Using the data in Problem 8, test whether there is a difference in endotoxin levels between children living within 5 miles of an operating farm as compared to those living at a distance of 50 miles or more. Run the appropriate test at a 5% level of significance.

1. An investigator wants to test whether there is a difference in endotoxin levels in children who are exposed to endotoxin as a function of their proximity to operating farms. The following are endotoxin levels in units per milligram of dust sampled from children's mattresses, organized by children's proximity to farms.

Within 5 miles	54	62	78	90	70
5-24.9 miles	28	42	39	81	65
25-49.9 miles	37	29	30	50	53
50 miles or more	36	19	22	28	27