b Compare the number of times the event we are interested in occurs to the number of times the experiment is done.
A
a 1/6 or ≈ 0.167
B
b 39/250 or 0.156
Practice makes perfect
a The students in math class performed an experiment by rolling a standard number cube. In order to find the theoretical probability of rolling the number 1 with the number cube, we will use the Probability Formula.
P = Favorable Outcomes/Possible Outcomes
There are 6 possible outcomes of rolling a standard number cube, as it has 6 sides with the numbers from 1 to 6. There is only 1 side with the number 1 on it, so the number of favorable outcomes is 1. Now we have enough information to calculate the desired probability.
The theoretical probability of rolling the number 1 with the number cube is 16, or about 0.167.
b This time we want to find the experimental probability of rolling the number 1 from the experiment. Let's look at the results in the given table.
Outcome
1
2
3
4
5
6
Times Rolled
39
40
47
42
38
44
We will compare the number of times the event we are interested in occurs to the number of times the experiment is done.
P = Times the event occurs/Times the experiment is done
In our case, the number of times that the experiment was done is the total number of times a student rolled the standard cube. Therefore, we need to add up the numbers from the second row of the table.
39+40+47+42+38+44 = 250
The event we are interested in is the outcome that a 1 is rolled on the cube. According to the table. this happened 39 times. We have enough information to calculate the desired experimental probability.
P = Times the event occurs/Times the experiment is done
