|Question 14Math

Source Texts

Text
For a study, a group of chipmunks will be selected from a habitat... and a group of prairie dogs will be selected... some in treatment group, some in control group. [cite: 1935, 1936]
Which of the following is necessary for this study to attempt to establish a cause-and-effect relationship between two variables?
The number of chipmunks... equals the number of prairie dogs...
A
The chipmunks and the prairie dogs are randomly assigned to the treatment and control groups.
B
The chipmunks and the prairie dogs are randomly selected from their respective habitats.
C
The average age... is equal...
D