The experimental designs in the given scenarios are: completely randomized design, block design, matched pairs design, observational study, and completely randomized design.
The experimental designs can be classified as follows:
Scenario A: This scenario represents a completely randomized design. The sample of 100 people was divided into two groups and each group was assigned to a different hypnosis exercise randomly.
The responses of the participants were recorded at the end of the experiment.
Scenario B: This scenario represents a block design. The sample of 50 vegetable plants was grouped into pairs based on type and size. Each pair was then assigned to a different fertilizer randomly.
This design helps control for the variability between the pairs of plants.
Scenario C: This scenario represents a matched pairs design. Two 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 car. This design helps eliminate the influence of potential confounding factors.
Scenario D: This scenario represents an observational study. A random sample of 100 lakes was selected to compare the diversity of birds among the lakes.
Data on bird count and species identity were recorded for each lake. This design does not involve any manipulation or random assignment.
Scenario E: This scenario represents a completely randomized design. Eighteen drivers were randomly assigned to three different driving simulations.
The performance of each driver was evaluated after each simulation. This design allows for statistical comparisons between the groups.