Question

What does random assignment do in an experiment that makes it so useful?

		It allows us to be able to interpret the results of an experiment because we know that the groups we study are not the same at all and we want them to be as different as possible.
		It gives us confidence that the statistics we use in experiments can't be made up.
		It provides us with some confidence that the groups we are studying are basically the same so we can see what happens when we change one thing.
		It helps us put people in the right order for understanding how to design an experimental condition.

Answer 1

The correct answer is:

It provides us with some confidence that the groups we are studying are basically the same so we can see what happens when we change one thing.

Random assignment means using chance procedures to make sure that each participant has the same chance of being selected to any given group. This ensures uniformity among groups, reducing bias and giving us confidence that the groups we are studying are basically the same so we can see what happens when we change one thing.

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