In an analysis of hunting by African lions, biologists filmed prey captures from the safety of their vehicles. Prey captures were then divided into a sequence of events. One of the events is the stalk, defined as the reduction of predator-prey distance for prey that has been specifically targeted.
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 wildebeests and zebras from a simple random sample of 159 kills appear in the table below.
|
Characteristic
|
Numeric
value
|
|
Mean stalking time
|
31.6 min
|
|
Standard deviation of stalk time
|
16.4 min
|
|
Proportion of stalks of the crouching type
|
0.92
|
By monitoring radio-collared lions for many years, biologists believe that the average stalking time among all prey is approximately 25.6 minutes. Do the data above provide evidence that for this population of lions the average time to stalk wildebeests and zebras is different from what was originally thought?