Experimental probability is?

The ratio of the number of times an event occurs to the total number of trials or times the activity is performed.

Theoretical probability is probability done without any actual experimentation. For example, if half of something is blue and the other half is red, there's a 50% chance of ending up with either.

Experimental probability is based on a given set of data. For instance, if some dude scored a goal two times but missed the next two he'd have a 50% chance of getting the next one.