17. You want to test a new athlete's-foot treatment. You test men and women separately, randomly dividing them into treatment and control groups. The treatment groups receive the new treatment and the control groups receive an inert powder that resembles the treatment. Neither the subjects nor the test administrators know which groups receive the treatment and which groups receive the inert powder. At the end of the experiment, all subjects are asked to rate their degree of relief from athlete's foot. These scores are compared between groups. Which of the following groups of elements were present in this study? a. Randomization, blocking, placebo, comparative, double-blind

b. Comparative, randomization, placebo, blind

c. Double-blind, randomization, comparative, placebo

d. Randomization, stratified sample, placebo, blind, treatment

e. Double-blind, control, observational, blocking

a. Randomization, blocking, placebo, comparative, double-blind

Step-by-step explanation:

1. Randomization is the process of assigning the subjects in an experiment to any of the treatment groups. This was applied in this experiment when the researcher randomly divided the men and the women into treatment and control groups.

2. Blocking is introduced in an experiment in order to remove nuisance factors. The researcher introduced blocking in this experiment when he divided the men and women on the basis of gender.

3. The Placebo is the inert powder that was given to a group. It has no effect on the participants who receive it.

4. Comparative research compares the result from two groups. This is seen in this research hen the researcher compares the scores between the groups.

5. A double-blind experiment is one where neither the subjects nor the test administrators know which groups receive a treatment. This factor is present in this test.  

(5x-1)^2= (5x)^2-2(5x)×1+(1)^2=25x^2-10x+1