When Wildlife Biologists Study Small Animals, the Animals Are Trapped

Essay

When wildlife biologists study small animals, the animals are trapped and then
anesthetized to prevent discomfort to the animal. 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. Heartbeat Rate (heartbeats/min)
$\begin{array}{|c|c|c|c|}\hline \text { Group } & \begin{array}{c}\text { Sample } \\\text { size }\end{array} & \text { Mean } & \begin{array}{c}\text { Standard } \\\text { deviation }\end{array} \\\hline \text { Summer } & 24 & 347.5 & 80.83 \\\text { Winter } & 13 & 360.0 & 133.04 \\\hline\end{array}$

An initial analysis of the data revealed that it was reasonable to assume the distributions of heartbeats for both seasons are approximately normal. It was also judged to be reasonable to regard these samples as representative of the Allegheny woodrat population.
a) Test the hypothesis of no difference between woodrat mean heartbeat rates for winter and summer. b) Do the data indicate that the mean heartbeat rates differ? Provide an appropriate
statistical justification using your response in part (a).