Question

For questions # 5 & 6 determine the experimental design used. Give reasons for your answer in each case. 5. A researcher wants to conduct a study to compare the lasting quality 3 different paints (PI, P2, P3) being considered for lane marking on highways. There are 12 sections of highway available for applying the paint. Each type of paint is randomly assigned to 4 of the highway sections. 6、 The relationship between 6 different doses of a drug that increases blood pressure and the actual amount of increase in mean diastolic blood pressure was investigated in a laboratory experiment. 12 rabbits all received, in random order, the 6 different dose levels of the drug, with a suitable interval

Answer 1

5.

Here the treatments are P1, P2 and P3.

Now, there are 12 sections where each painting is randomly assigned to 4 highways.

So, here this is a problem of Randomised Block Design, where there are 3 treatments, 4 blocks and each block has 3 sections.

6.

6 different doses of drugs can be considered as treatments. Now, 12 rabbits are the experimental units. Now, each drug is applied randomly with a suitable interval. This can be considered as a Completely Randomized Design with 6 treatments and 2 replicates.