Experimental Probability

Experimental probability: method

Experimental probability is based on results from data or trials, not on a theoretical model. For an event, use

experimental probability = number of times the event occurs / total number of trials

Then simplify the fraction if possible.

Step-by-step

1. Identify the event you are asked about. This could be a specific outcome, category, or result.
2. Count the favorable outcomes: how many times that event happened in the experiment or data set.
3. Count the total trials: include every valid attempt or observation.
4. Write the probability as a fraction: favorable / total.
5. Simplify the fraction to lowest terms.

Example structure

If an outcome occurs 8 times out of 20 trials, the experimental probability is

8/20 = 2/5

Quick check

Make sure:

• the numerator is the count for the event only,
• the denominator is the total number of trials,
• the final fraction is reduced.

If the answer is given as a decimal or percent in a different context, convert only if the question asks for it. Here, the key skill is forming the fraction correctly and simplifying it.