In an Analysis of Hunting by African Lions, Biologists Filmed

question 17

Essay

In an analysis of hunting by African lions, biologists filmed prey captures from the
safety of their vehicles. The capture of prey was divided into a sequence of events for
study, one of which is the stalk, defined as the reduction of predator-prey distance for
prey that has been specifically located and the prey is unaware of or minimally
alarmed by the predator. The investigators identified two types of stalk: (a)
"crouching," -- the lion is concealed and either the lion advances toward the prey or
the prey advances (unaware) toward the lion, and (b) "running," -- the lion is less
concealed and advances toward the prey in a rapid manner.
Data on lions' stalks of Thomson's and Grant's gazelles from a random sample of 151
kills is summarized in the table below. $$\begin{array} { | l | l | } \hline { \text { Characteristic } } & { \begin{array} { c } \text { Numeric } \\\text { value }\end{array} } \\\hline \text { Mean stalking time } & 24.9 \mathrm {~min} \\\text { Standard deviation of stalk time } & 3.0 \mathrm {~min} \\\text { Proportion of stalks of the crouching type } & 0.79 \\\hline\end{array}$$ Researchers believe that the proportion of stalks that are the crouching type is about 0.87. Do the data above provide evidence that the researchers' belief is incorrect and
that the proportion of crouching stalks of Thomson's and Grant's gazelles is different
from 0.87?