Question

Classify each scenario according to its experimental design. Some categories may contain more than one scenario.

Scenario A: A sample of 100 people was separated into children and adults. The members of each group were randomly assigned to two different hypnosis exercises. The responses of each person were recorded at the completion of the experiment.

Scenario B: A sample of 50 vegetable plants was grouped into pairs of similar individuals based on type and size. Then, within these pairs, each vegetable plant was assigned to a different fertilizer. After three weeks, the responses of each pair were analyzed to compare the effects of the fertilizers.

Scenario C: Twenty race cars were assigned to drive two laps, once with fuel A and once with fuel B. The order of treatments was randomized for each race car. The lap times of each race car were recorded to compare the effects of the two different treatments.

Scenario D: A random sample of 100 lakes was selected in a particular state. To compare the diversity of birds among the lakes, the count and species identity of all birds were recorded for each lake over a 24-hour period.

Scenario E: Eighteen drivers were randomly assigned to three different driving simulations. At the conclusion of each simulation, the performance of each driver was evaluated.
Chose which scenario (A,B,C,D,E)

Completely randomized design SCENARIO_________

Block design (not matched pairs) SCENARIO _________

Matched pairs design SCENARIO ____________

Observational study SCENARIO ___________

Answer 1

Scenario A is a Completely randomized design; Scenario B is a Matched pairs design; Scenario E is a Block design; and Scenario D is an Observational study. Scenario C is a crossover design but was not requested in the available choices.

Step-by-step explanation:

Classification of Experimental Designs

When classifying experimental designs, each scenario provided correlates with a specific type of design based on how participants or subjects are assigned and how the studies are conducted. Here are the classifications for the given scenarios:

Completely randomized design: Scenario A fits this design as individuals within each group (children and adults) were randomly assigned to two different hypnosis exercises.

Block design (not matched pairs): Scenario E falls under this design since the eighteen drivers were randomly assigned to three different driving simulations, forming blocks based on the simulation they received.

Matched pairs design: Scenario B is an example of this design; vegetable plants were grouped into pairs, and each plant within the pair given a different fertilizer, creating matched pairs based on plant type and size.

Observational study: Scenario D represents an observational study as no intervention was applied. Instead, the count and species identity of birds were recorded for each lake.
As for Scenario C, it can be classified as a crossover design, since each race car received both treatments (fuel A and fuel B) in a randomized order, meaning each car served as its own control at different points in the experiment.