When wildlife biologists study small animals, the animals are trapped and then anesthetized to prevent discomfort to the animal and safety from disease transmission to the biologist. A study of the effect of the anesthetic, Isoflurane, on Allegheny woodrats (Neotoma magister) resulted in the heartbeat data presented below. The biologists were interested in comparing the effects of Isoflurane in two different seasons, winter and summer.
Pulse (heartbeats/min)
Group Summer Winter Sample size 24 13 Mean 347.5 360.0 Standard deviation 80.83 133.04
An initial analysis of the data revealed that it was reasonable to assume the distributions of heartbeats for both seasons are approximately normal.
a) Construct a 95% confidence interval for the difference in heartbeat rate for winter and summer. It was also judged to be reasonable to regard these samples as representative of the Allegheny woodrat population.
b) Do the data indicate that the heartbeat rates differ? Justify your answer statistically using your response in part (a).