To calculate how many people you need in your experiment, you need to know 3 things:

1. How many groups are in your experiment?

• In an A/B experiment with a control and treatment group, you have 2 groups.
• In a 2 x 2 Multi-Variable experiment with 1 control and 3 treatment groups, you have 4 groups.
• The more groups you have, the more people you need.
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