Question

Look, Ma, no hands! Does talking on a hands-free cell phone distract drivers? Researchers recruit $40$student subjects for an experiment to investigate this question. They have a driving simulator equipped with a hands-free phone for use in the study. Each subject will complete two sessions in the simulator: one while talking on the hands-free phone and the other while just driving. The order of the two sessions for each subject will be determined at random. The route, driving conditions, and traffic flow will be the same in both sessions.

a. What type of design did the researchers use in their study?

b. Explain why the researchers chose this design instead of a completely randomized design.

c. Why is it important to randomly assign the order of the treatments?

d. Explain how and why researchers controlled for other variables in this experiment.

Short answer

(a) The matched pair design is used by researchers.

(b) The researchers chose this design instead of a completely randomized design because it eliminate variability.

(c) It is important to randomly assign the order of the treatments because we will experience confounding variable.

(d) The researchers controlled for other variables in this experiment by controlling and sure the routes and rules.

Step-by-step solution

Part (a) Step 1: Given information

We need to find the type of design did the researchers use in their study.

Part (a) Step 2: Explanation

We know that

Each subject is administered for both treatments i.e. random order and comparison to themselves.

Therefore,

The matched pair design is used by researchers.

Part (b) Step 1: Given information

We need to find the reason for researchers chose this design instead of a completely randomized design.

Part (b) Step 2: Explanation

We know that

Matched pair design helps in

• eliminating the variability in subjects by comparing each subject response to the other and itself.

Therefore,

The researchers chose this design instead of a completely randomized design because it eliminate variability.

Part (c) step 1: Given information

We need to find the importance of randomly assigning the order of the treatments.

Part (c) Step 2: Explanation

It's crucial to allocate the treatments in a random order since we expect the participants to do better on their second attempt because they'll have more experience. As a result, we could expect the experience to be a confounding variable.

If we then assign the treatments in a random order, both treatments will appear as the first attempt for some subjects and the second attempt for others, allowing us to compare the results of the two treatments while knowing that the differences between the two attempts will differ due to experience.

Part (d) Step 1: Given information

We need to find the way the researchers controlled for other variables in this experiment.

Part (d) Step 2: Explanation

We know that

Researchers make sure that the factors that will affect the driving situation does not produce any variability to response of controlling them.

Therefore,

The researchers controlled for other variables in this experiment by controlling and sure the routes and rules.