Section 9.3 Experimental Probability 401
Comparing Experimental and Theoretical Probabilities
The bar graph shows the results of rolling a number cube
50 times. What is the experimental probability of rolling an
odd number? How does this compare with the theoretical
probability of rolling an odd number?
Find the experimental probability of rolling a 1, 3, or 5.
The bar graph shows 10 ones, 8 threes, and 8 ﬁ ves.
So, an odd number was rolled 10 8 8 26 times in
a total of 50 rolls.
The experimental probability is
0.52 52%. The theoretical
0.5 50%. The experimental and theoretical
probabilities are similar.
3. In Example 3, what is the experimental probability of rolling a
number greater than 1? How does this compare with the
theoretical probability of rolling a number greater than 1?
Rolling a Number Cube
1. In Example 1, what is the experimental probability that your
next email is not junk?
2. At a clothing company, an inspector ﬁ nds
5 defective pairs in a shipment of 200 jeans.
a. What is the experimental probability of
a pair of jeans being defective?
b. About how many would you expect to be
defective in a shipment of 5000 pairs of jeans?
An odd number was rolled 26 times.
There was a total of 50 rolls.
Experimental Probability Theoretical Probability
number of times the event occurs
total number of trials
number of favorable outcomes
number of possible outcomes
There are 3 odd numbers.
There is a total of 6 numbers.