Exam 15: Learning From Categorical Data

Juvenile ground squirrels respond to predators by making what are known as "alarmcalls. These calls can alert others to danger. Newly weaned squirrels emerge fromthe nest at about 25 days of age. Do the squirrels emerge from the nest withautomatic responses to alarm signals, or are the responses learned? To address thisquestion a biologist played recordings of alarm calls for three samples of groundsquirrels and observed their responses. She reasoned that if the pattern of responseswas the same for the different age groups the squirrels must be responding by instinct.On the other hand, if the responses differ with the age of the squirrels, the youngsquirrels may be learning to respond to the alarm calls. Her data for the responses to

Juvenile ground squirrels respond to predators by making what are known as "alarmcalls. These calls can alert others to danger. Newly weaned squirrels emerge fromthe nest at about 25 days of age. Do the squirrels emerge from the nest withautomatic responses to alarm signals, or are the responses learned? To address thisquestion a biologist played recordings of alarm calls for three samples (by age) ofsquirrels and observed their responses. She reasoned that if the pattern of responseswas the same for the different age groups the squirrels must be responding by instinct.On the other hand, if the responses differ with the age of the squirrels the youngsquirrels may be learning to respond to the alarm calls. Her data for the responses to a single whistle are presented below for each of the three age samples: Is there convincing evidence that the responses to a single whistle are not the samefor the different age groups? Test the relevant hypothesis at the 0.05 level.