Question 5 • Probability and Statistics with Applications Honors Sem-1-FL-1210300 (2024-2025)
A biologist wonders if the life span of bats will be affected by two new food sources from invasive species moving into an area. To conduct the experiment, the biologist needs three treatment groups: a group where the diet will not include invasive species (control), a group where the diet will include one invasive species (treatment group 1), and another group where the diet will include the other invasive species (treatment group 2). The biologist chooses the first cloud-free night and catches the first 18 bats that fly out of a cave, placing them into three equal groups of six bats. To decide the treatment for each group, the biologist places three slips of paper labeled control, treatment group 1, and treatment group 2 in a hat and randomly selects 2 slips of paper. The first piece of paper gives the treatment for the first group, the second piece of paper gives the treatment for the second group, and the remaining treatment is given to the third group.
Answer
A
The biologist did not use proper labeling on the pieces of paper.
B
The biologist did not use the appropriate number of treatment groups.
C
The biologist did not randomly assign the individual bats to the treatment groups.
D
The biologist did not randomly choose the weather on the night for bat capture.
Explanation
The treatments were randomly assigned to the three groups, but the bats themselves were not randomly assigned to those groups. The first 18 bats to leave the cave could differ in ways related to life span, and grouping them without random assignment could make the groups unequal before treatment begins. The biologist should randomly assign the 18 bats to the three groups of six.
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