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A state Wildlife and Fisheries agent is trying to stimulate the growth of the population of a certain type of fish. She will conduct an experiment that involves randomly assigning $3\text{ different treatments}$ to $36\text{ fish}$ to determine which treatment will cause the largest amount of weight gain in the fish. The agent wants to make sure that the $3\text{ treatment groups}$ each have exactly $12\text{ fish}$.

Which of the following methods should be used to assign the treatments?

A

Catch $36\text{ fish}$. For each fish roll a six-sided number cube. If the cube shows a $1$ or $2$, the fish will receive treatment 'A'. If the cube shows a $3$ or $4$, the fish will receive treatment 'B'. If the cube shows a $5$ or $6$, the fish will receive treatment 'C'.

B

As each fish is caught, draw a number from a random digit table. If the number is $1$, $2$, or $3$, the fish will receive treatment 'A'. If the number is $4$, $5$, or $6$, the fish will receive treatment 'B'. If the number is $7$, $8$, or $9$, the fish will receive treatment 'C'. If the number is $0$, a new number will be drawn. If a treatment group already has $12\text{ fish}$ then another number will be chosen to assign the fish to one of the other groups.

C

The first $12\text{ fish}$ caught will be assigned to treatment 'A', the second $12\text{ fish}$ to treatment 'B' and the last $12\text{ fish}$ to treatment 'C'.

D

Catch $36\text{ fish}$ and assign each fish a unique number between $1$ and $36$. Write the numbers from $1$ to $36$ on separate slips of paper. Place the slips in a fish bowl and mix them up. Draw $12\text{ slips}$ of paper. The fish corresponding to those numbers will receive treatment 'A'. Draw $12\text{ more slips}$ of paper. The fish corresponding to those numbers will receive Treatment 'B'. The remaining fish will receive treatment 'C'.

E

All of these methods will randomly assign the treatments to $3\text{ groups}$ of $12\text{ fish}$.

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