Question

A group of investigators suspected that rats trained to run on a wheel against a drag would run significantly faster if fed a 20% sucrose solution along with their daily diet. Before the trials began, all 100 rats ran a wheel against a draft to measure their baseline speed. Then 50 rats were randomly assigned to receive the normal diet plus the sucrose supplement and 50 rats were randomly assigned to receive only the normal diet for one week. At the end of the week, all rats ran on the wheel against a drag to see how fast the rats ran relative to their initial speed.

What is type of experimental design is being used here?

What is the independent variable in this study?

What are the levels of the independent variable in this study?

How is the dependent variable measured in this study?

What is the design flaw (confounding variable) in this study?  

Answer 1

1. A non equivalent control group design is being used.

2. The independent variable is sucrose.

3. The levels of the independent variable are sucrose supplement and no sucrose supplement.

4. The dependent variable is running speed.

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