I want to return a value of true or false but force it to randomly return false 3% of the time [duplicate]

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• Random boolean with weight or bias 6 answers

From user input of either char a or char b as an answer. I want to return a value of true or false from user input. Then count the number of selections between two possibilities per individual user input. Then force it to randomly return false 3% of the time. The purpose is to alter the expected outcome with a reward.

How do I go about doing this? I am new to this concept.