# Predicting vs. Observing Probability

There are two ways to calculate probability - either by using math to predict, or 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, 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 or about and Tails is or about
- Theoretical probability of flipping Heads is and Tails is