There are two ways to calculate probability:
- using math to predict
- by actually observing the event and keeping score.
Theoretical probability uses math to predict the outcomes. Just divide the favorable outcomes by the possible outcomes.
Experimental probability is based on observing a trial or experiment, counting the favorable outcomes, and dividing it by the total number of times the trial was performed.
Let’s look at this example: we tossed a coin 36 times and recorded the outcomes H for Heads and T for Tails:
H, T, H, H, T, T, H, T, T, T, T, T, T, T, T, H, H, T, H, H, T, H, H, H, H, T, H, H, T, H, H, T, H, H, T, H
Based on this experiment:
- Experimental probability of flipping Heads is 19/36 or about 53% and Tails is 17/36 or about 47%
- Theoretical probability of flipping Heads is 50% and Tails is 50%