Classify the experiments according to their experimental designs. Some designs may be used more than once. Studying. A sample of 30 students was separated into upperclassmen and lowerclassmen. The members of each group were randomly assigned to two different studying techniques. The responses of each student were recorded at the completion of the experiment. Rats. A sample of 50 rats was grouped into pairs of similar individuals based on species, age, and weight. Then, within these pairs, each rat was assigned to a different diet. After three weeks, the responses of each pair were analyzed to compare the effects of the diets. Race car fuel. 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. Building age. A random sample of 100 houses was selected in a particular city. To assess how building age influences energy consumption, the construction year and energy usage over a one-year time period were recorded for each house. Driving simulations. Eighteen drivers were randomly assigned to three different driving simulations. At the conclusion of each simulation, the performance of each driver was evaluated.

Classify the experiments according to their experimental designs. Some designs may be used more than once.

Studying. A sample of 30 students was separated into upperclassmen and lowerclassmen. The members of each group were randomly assigned to two different studying techniques. The responses of each student were recorded at the completion of the experiment.

Rats. A sample of 50 rats was grouped into pairs of similar individuals based on species, age, and weight. Then, within these pairs, each rat was assigned to a different diet. After three weeks, the responses of each pair were analyzed to compare the effects of the diets.

Race car fuel. 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.

Building age. A random sample of 100 houses was selected in a particular city. To assess how building age influences energy consumption, the construction year and energy usage over a one-year time period were recorded for each house.

Driving simulations. Eighteen drivers were randomly assigned to three different driving simulations. At the conclusion of each simulation, the performance of each driver was evaluated.