Question

Eat well and exercise Most American adolescents don’t eat well and don’t exercise enough. Can middle schools increase physical activity among their students? Can they persuade students to eat

better? Investigators designed a “physical activity intervention” to increase activity in physical education classes and during leisure periods throughout the school day. They also designed a “nutrition intervention” that improved school lunches and offered ideas for healthy home-packed lunches. Each participating school was randomly assigned to one of the interventions, both interventions, or no intervention. The investigators observed physical activity and lunchtime

consumption of fat.

Short answer

Experimental unit: Middle Schools.

Explanatory variables: whether the service was designed for physical exercise and whether diet.

Program offered.

Treatments: $4$ drug varieties planned by experts.

Response variable: physical exercise and fat intake at lunchtime.

Step-by-step solution

Given information

The researchers devised a "physical activity intervention" to encourage students to be more active in physical education classes and during free time during the school day. They also created a "nutrition intervention" that enhanced school lunches and provided healthy home-packed lunch alternatives. One of the interventions, both interventions, or no interventions were randomly assigned to each participating school. The researchers looked at physical activity and fat consumption during lunchtime.

Concept

The treatments are randomly assigned to all of the experimental units in a completely randomized design.

In a double-blind experiment, neither the subjects nor the people who interact with them and assess the response variable are aware of the treatment they received.

Observational research looks at people and assesses factors of interest without trying to affect their responses.

Individuals are purposely subjected to a treatment in order to measure their responses in an experiment.

Explanation

Middle Schools as an experimental unit

Explanatory variables include whether the service was intended for physical activity and whether the diet was followed.

The program is available.

Experts have proposed four medication kinds as treatments. The following are the four treatments: $1)$ the operation's interference $\left(2\right)$ diet participation, and$\left(3\right)$ both. $4)$no participation at all.

Physical activity and fat intake at lunchtime are the response variables.