Why was each participant randomly assigned the order in which they used the two layouts?

Question

Answer

So that the paired t-test no longer needs the differences to be roughly normal.

Answer

So that the times from different participants are independent of each other.

Answer

So that the sample of 30 participants represents all staff in the company.

Answer

So that learning or tiredness effects are not mixed up with the layout effect.

Answer

So that every participant has exactly the same average time for the two layouts.

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