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 typeify each 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

Completely randomized design: A, C, E

Block design (not matched pairs): B

Matched pairs design: Not represented in the given scenarios

Observational study: D

How did we arrive at this classification?

Let's classify each scenario according to its experimental design:

1. Completely randomized design SCENARIO: A, C, E

- Scenario A: Individuals were randomly assigned to hypnosis exercises.

- Scenario C: Race cars were assigned to drive laps with fuel A and B in a randomized order.

- Scenario E: Drivers were randomly assigned to different driving simulations.

2. Block design (not matched pairs) SCENARIO: B

- Scenario B: Vegetable plants were grouped into pairs based on type and size, and then each pair was assigned to a different fertilizer.

3. Matched pairs design SCENARIO: Not represented in the given scenarios

- Matched pairs design involves pairing similar individuals and assigning different treatments within each pair. None of the scenarios explicitly describes this design.

4. Observational study SCENARIO: D

- Scenario D: Lakes were selected, and the diversity of birds was observed. This scenario does not involve experimental manipulation but rather the observation of existing conditions.

In conclusion,

- Completely randomized design: A, C, E

- Block design (not matched pairs): B

- Matched pairs design: Not represented in the given scenarios

- Observational study: D