The experimental probability is given by the results of the experiment.
The coin landed heads up 12 out of 20 times. Divide the amount of times it landed heads up by the amount of times you flipped the coin:
Multiply this decimal by 100 to get the percentage:
The experimental probability of the coin landing heads up is
12/20, or 3/5, or 60%.
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The theoretical probability is given by the chances of landing the coin heads up.
There are two outcomes: the coin landing heads up, and the coin landing tails up. Out of two outcomes, you want one.
Theoretical probability is given by the amount of wanted possibilities over the total possibilities. You want 1 out of 2 to occur, so the theoretical probability is
1/2, or 50%.