Question

Killing weeds A biologist would like to determine which of two brands of weed killer, X or Y, is less likely to harm the plants in a garden at the university. Before spraying near the plants, the biologist decides to conduct an experiment using$24$individual plants. Which of the following two plans for randomly assigning the treatments should the biologist use? Why?

Plan A: Choose the$12$healthiest-looking plants. Then flip a coin. If it lands heads, apply Brand X weed killer to these plants and Brand Y weed killer to the remaining$12$plants. If it lands tails, do the opposite.

Plan B: Choose$12$of the$24$plants at random. Apply Brand X weed killer to those$12$plants and Brand Y weed killer to the remaining$12$plants.

Short answer

Plan B should be used because it follows the principle of random assignment.

Step-by-step solution

Given Information

We are given that the biologist wants to check whether from X or Y which will harm the plans, and that they have two plans, Plan A and Plan B, and we have to find out which plan is following random assignment.

Explanation

According to the question, a biologist has to choose the plan that follows random assignment. Random assignment means that the particular should be choose randomly but in Plan A twelve plants are choose by seeing their healthiness which means randomization is not present here while in Plan B all twenty four plants are taken and twelve are given X weed while other are given Y weed which means randomly plants are chosen.

Hence, Plan B is the correct way.