Logging in rain forest. Conservationists have despaired over destruction of tropical rain forest logging, clearing and burning. These words begin a report on a statistical study of the effects of logging in Borneo. Here are the data on the number of tree species in 12 unlogged forest plots and 9 similar plots logged 8 years earlier. Use 5% level of significance.

Given:

Unlogged 32 28 22 20 15 21 13 13 19 13 19 13

Logged 17 4 18 14 18 15 15 10 12