Question

3. Toxaphene is an insecticide that has been identified as a pollutant in the Great Lakes ecosystem. To investigate the efffect of toxaphene exposure on animals, groups of rats were given toxaphene in their diet. The paper “Reproduction Study of Toxaphene in the Rat” (J. of Environ. Sci. Health(1988):101-126) reported weight gains (in grams) for rats given a low dose (4 ppm) and for control rats whose diet did not include the insecticide. The accompanying table gives data for male rats.

Group n x̅ s

Control 15 529 66

Low Dose 15 551 71

a. Is there sufficient evidence that a low dose of toxaphene increases mean weight gain for male rats? b. Estimate the difference in mean weight gain for control and low dose rats using a 90% confidence interval.

Answer 1