Question: DDT in rats Poisoning by the pesticide DDT causes convulsions in humans and other mammals. Researchers seek to understand how the convulsions are caused. In a randomized comparative experiment, they compared 6 white rats poisoned with DDT with a control group of 6 unpoisoned rats. Electrical measurements of nerve activity are the main clue to the nature of DDT poisoning. When a nerve is stimulated, its electrical response shows a sharp spike followed by a much smaller second spike. The researchers measured the height of the second spike as a percent of the first spike when a nerve in the rat's leg was stimulated.33 For the poisoned rats, the results were
12.207 16.869 25.050 22.429 8.456 20.589
The control group data were
11.074 9.686 12.064 9.351 8.182 6.642
(a) Do these data provide convincing evidence that DDT affects the mean relative height of the second spike's electrical response?
(b) Interpret the P-value from part (a) in the context of this study.