Question

Q1: Briefly explain if the situation describes an observational or experimental study:

a. A researcher stood at a busy intersection to see if the color of the automobile that a person drives is related to running red lights.

Q2: A researcher wishes to run an experiment using 40 right-handed people to determine if applying an ointment on the dominant hand promotes healing of skin condition:

a. Describe the experiment if we use a randomized comparative design.

b. Describe the experiment if we use a matched pairs design.

Answer 1

1. a) This is an observational study as the researcher is just observing the color of the automobiles and the lights. The researcher hasn't intervened in the study at all.

2. a) If we use a randomized comparative design, the researcher will divide 40 right-handed people randomly into two groups. The ointment will be applied on the dominant hand in one group while on the left hand in the other group. The healing of the skin will be observed and the difference will be checked.

b) If we use a matched pair design, the subjects will be grouped into pairs based on some blocking variable like gender, age etc. For example, Pair 1 might be two men with age 23 , pair 2 might be two women with age 32. Within each pair, the subjects are assigned different treatments (ointment applied on right hand and left hand).