How do you decide the number of participants to assign to a control group?

Question

My study has 100 participants. I have a table to randomly assign a treatment and control group. I can't find literature indicating how many participants should be assigned to the control group.

Answer 1

moderator-wise, you can only have 15, and it's up to the owner as to how many they need or have

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Answer 2

i would say 50%

Answer 3

Really depends on what you are testing, but the smaller your control group, the larger your margin for error. so to play absolutely safe, make your control group (statistically) identical to your study group. See link below for more information:

http://en.wikipedia.org/wiki/Scientific_...

Answer 4

I say no more then one can handle but 15-30 each control er