A biologist would like to determine which of two brands of w

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 assign- ing 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 remain- ing 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.

Solution

Plan B is correct because,if he uses plan A and discovers that the plants that had weed killer X apply will better he will not know if this is because if weed killer X or because these healthier plants to begin with .Hence Plan B is best