Question

1.13. 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

Experimental designs in the scenarios classify as follows: Scenario A and Scenario E are completely randomized designs, Scenario B utilizes a block design, Scenario C is an example of a matched pairs design, and Scenario D is an observational study.

Step-by-step explanation:

Classifying experimental designs involves understanding how subjects are grouped and how treatments are administered. Here is the classification of each scenario:

1. Completely randomized design: SCENARIO A and SCENARIO E fall under this category as individuals are randomly assigned to treatments without any prior grouping.
2. Block design (not matched pairs): SCENARIO B is an example of a block design where similar individuals (vegetable plants) form blocks before being randomly assigned to different treatments.
3. Matched pairs design: SCENARIO C is a matched pairs design because each race car serves as its own control by receiving both treatments in a random order.
4. Observational study: SCENARIO D is an observational study where no treatments are imposed, and researchers merely observe and record data on bird diversity in lakes.

The selection and assignment methods in experimental design are critical for reducing bias and maintaining the integrity of the conclusions drawn from the data.