Question

a group of researchers wants to study the effect of listening to music at different volumes on driving reaction times. they recruit 100 volunteers.

while music plays in the car at one of two volume levels, each subject encounters a number of signs, some of which require braking, and their reaction times are recorded. the subjects repeat the experiment at the other volume level. the order of the conditions is randomly assigned for each subject.

what type of experiment design is this?

choose 1 answer.

a stratified

b randomized block

c systematic

d completely randomized

Explanation:

1. Analyze each option:

• Stratified: Involves dividing the population into strata and sampling from each. Not applicable here as no stratification of groups.
• Randomized block: In this design, subjects are blocked (here, each subject is a block as they experience both conditions), and treatments are randomly assigned within blocks. Here, each subject (block) does both volume levels (treatments) with random order, matching this design.
• Systematic: Uses a fixed interval to select samples, not related to experiment design here.
• Completely randomized: Treatments are randomly assigned to subjects, but here each subject gets both treatments, so not this.

Answer:

B. Randomized block