Question

Scientists are studying the two primary vocalizations made by Belding’s ground squirrels (Urocitellus beldingi). The trill call consists of a series of medium-pitched notes given rapidly, while the whistle call consists of a single high-pitched note. The objective of the experiment is to determine the function of each vocalization. Recordings of the calls were played to four different groups of squirrels, and the response of each individual squirrel was documented. The responses are summarized in Table 1.

Table 1. Response of ground squirrels to recorded vocalizations

Which of the following correctly identifies the dependent variable and the independent variable for the experiment?

Which of the following correctly identifies the dependent variable and the independent variable for the experiment?

• The independent variable is the percent of squirrels responding, and the dependent variable is the type of alarm call.

  A

• The independent variable is the percent of squirrels responding, and the dependent variable is the type of response.

  B

• The independent variable is the group of squirrels, and the dependent variable is the percent of squirrels responding.

  C

• The independent variable is the type of alarm, and the dependent variable is the percent of squirrels responding.

Answer 1

An independent variable in an experiment is that characteristic which is not affected by the other. In this case, the squirrel "responds" to different alarm types, which makes the squirrel to be the dependant variable whereas the alaram type is not in any way affected by the squirrel, which makes the alarm type to be the independant variable.

The right answer here is option C.

Option A would be wrong here as the squirrels are the ones responding to the alarm call, which actually makes the squirrels dependant variable.

Option B would be wrong too as the squirrels in the different groups do eventually respond to the alarms, making them the dependant variable.