Experimental Probability Review

Experimental Probabilities

I flipped a coin 10 times and these are my results

Comparing the theoretical probability to the experimental probability is a comparison of the expected results, theoretical, to the actual results, experimental, after running an experiment.

You expect heads to appear 50% of the time, but what actually happened is heads appeared 70% of the time.

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​Why is it different?

​If I were to conduct more trials, that is, flip the coin more than 10 times, he would notice something interesting begin to happen.

As the number of flips increases, the experimental probability begins to get closer and closer to the theoretical probability.

Multiple Choice

Suppose you flip a coin 430 times and it lands on heads 208 times. What is the experimental probability, to the nearest whole percent, of the coin landing on heads?

• 21%

• 48%

• 32%

Let's look at our results

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​Survey Results

Since there is no theoretical probability related to how people will respond to surveys, there is no way to tell if the experimental probability is close to the expected result.

However, if you continue to have more and more people complete the survey, you start to see the percentages hovering around a certain value.


The less they change the more reliable the results



* Companies use surveys like this to make decisions about their products. For example, since about 25% of people taking the survey say they like pepperoni, a frozen pizza company might make 25% of all the pizzas they sell to grocery stores pepperoni

Multiple Choice

John rolled a die 20 times, what is his experimental probability for rolling a 4?

$$\frac{7}{20\ }=\ ?\%$$

• 0%

• 35%

• 20%

Multiple Choice

Lisa conducted an experiment with a spinner, what is her experimental probability for spinning a 2 after spinning it 34 times?

$$\frac{9}{34}=\ ?\ \%$$

• 50%

• 26%

• 39%

Multiple Choice

What is the experimental probability of drawing a white or green marble from the bag?

$$P\left(white\ or\ green\right)\ =\ \frac{8}{28}$$

• 25%

• 29%

• 45%

Multiple Choice

What is the experimental probability of someone voting "Yes" on Bill 20.8A?

$$P\left(yes\right)\ =\ \frac{42}{63}$$

• 67%

• 63%

• 70%