A study was conducted by the Department of Zoology at the Virginia Polytechnic Institute and State University to determine if there is a significant difference in the density of organisms at two different stations located on Cedar Run, a secondary stream located in the Roanoke River drainage basin. Sewage from a sewage treatment plant and overflow from the Federal Mogul Corporation settling pond enter the stream near its headwaters. The following data give the density measurements, in number of organisms per square meter, at the two different collecting stations. Can we conclude, at the 0.05 level of significance, that the average densities at the two stations are equal?

Assume that the observations come from normal populations with differentvariances.

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Number of Organisms per Square Meter Station 2 2810 1330 3320 1230 2130 2190 Station 1 4980 5030 13,700 10,730 11.400 2800 4670 8130 6890 26,850 11.910 7720 860 2200 4250 17,660 7030 7330 22,800 1130 15,040 1690