To carry out a cool probability experiment, follow these easy steps:

1. Define the Experiment: First, figure out what you want to study. For instance, you might want to see how likely it is to roll a certain number on a die.

2. Establish the Sample Space: Next, list all the possible outcomes. If you have a six-sided die, the possible numbers are {1, 2, 3, 4, 5, 6}.

3. Conduct Trials: Now, it's time to get rolling! Do the experiment several times. For example, try rolling the die 100 times and write down what you get.

4. Collect Data: Count the results. If you rolled a 3 twenty times, make sure to record that number.

5. Calculate Experimental Probability: To find out the probability, use this simple formula:

   $P(E) = \frac{\text{Number of times you got the outcome}}{\text{Total rolls}}$

   So, if you want to know the probability of rolling a 3, it would be $P(3) = \frac{20}{100} = 0.2$.

6. Analyze Results: Finally, talk about what you found. Compare your results to what you expected. This will help you understand experimental probabilities better!