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Experimental Design

In an experiment designed to examine the effects of dieting and exercise on weight loss, subjects were randomly assigned to one of four conditions: (1) both dieting and exercise, (2) dieting but no exercise, (3) exercise but no dieting, and (4) neither dieting nor exercise. Results indicated that subjects not on a diet lost only three pounds whether or not they exercised. However, subjects who dieted lost 15 pounds if they exercised and 8 pounds if they did not exercise.

a) Is there a main effect for dieting? If so, describe the effect.
b) Is there a main effect for exercise? If so, describe the effect.
c) Is there an interaction effects? If so, describe the effect.
d) Is this a true experiment? Why, or why not?

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RESPONSE:

1. In an experiment designed to examine the effects of dieting and exercise on weight loss, subjects were randomly assigned to one of four conditions: (1) both dieting and exercise, (2) dieting but no exercise, (3) exercise but no dieting, and (4) neither dieting nor exercise. Results indicated that subjects not on a diet lost only three pounds whether or not they exercised. However, subjects who dieted lost 15 pounds if they exercised and 8 pounds if they did not exercise.

a) Is there a main effect for dieting? If so, describe the effect. Yes, because there is a ...

Solution Summary

By responding to the questions related to the scenario, this response addresses aspects of experimental design e.g. main effects of dieting asnd exercising, interaction effects and if it is a true experiment.

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