The table shows the relationship between the number of squares, X, and the permeter, y, of the figures they form. Which of the following statements is true? Select all that apply.
1
2.
3
4
Number of Squares, X
Perimeter, y
8
12
16
20

1. Placebos are used to randomly assign participants to treatment or control ?

False.

2. Using a random chance procedure to assign subjects to treatment or control reduces bias ?

True.

3. A well-designed placebo allows an experiment to be conducted blind. ?

False.

4. In an observational study, the investigators assign the subjects to treatment or control. ?

False.

5. In a blind experiment, the subjects do not know whether they are in the treatment group or control group. ?

True.

6. Placebos are used so that even the people who do not receive a treatment can benefit from the study. ?

True.

7. A placebo is used in all controlled experiments. ?

True.

8. Controlled experiments can be randomized or nonrandomized.

True.

Step-by-step explanation:

To enable the results from the control group to be compared to the results of a treatment group, placebos are administered to the control group while the treatment or independent group receives the real treatment.  Randomization is the process for assigning participants to treatment or control groups, not placebos.  The reason for using a random chance procedure to assign subjects to treatment or control groups is to reduce bias.