Kaplan Foundation B Practice Test

The main idea is how the probability is determined. Theoretical probability uses the setup of the experiment to figure out how likely each outcome is, based on counting the possible outcomes in the model. It’s a calculation about what could happen in an ideal sense, not what has actually happened when you test it. For a fair six-sided die, the theoretical probability of rolling a 4 is 1/6 because there is one favorable outcome out of six equally likely outcomes. This comes from the imagined sample space of all possible results. Experimental probability, on the other hand, comes from actual trials. You roll the die many times, record how often a 4 occurs, and compute the ratio of successes to total trials. If you roll 60 times and get a 4 six times, the experimental probability is 6/60 = 1/10. This can differ from the theoretical 1/6, but with more trials it tends to get closer to it (the Law of Large Numbers). So the statement that theoretical probability is based on possible outcomes and experimental probability is based on observed outcomes captures this essential distinction.