Step by Step Experimental Probability Directions
Probability
of one event
using the
total
possible
outcomes
provided
Probability
of 2 options/
events
“x or a y”
The graph shows the results of an experiment in which a number cube
was rolled 100 times. Find the experimental probability of rolling a 3
for this experiment.
Probability = number of times action occurs
Total number or number
of possible outcomes
=number of times 3 is rolled
100
experimental probability P = 16
100
4
25
=simplify =
What is the probability of rolling a 3 or a 6 if the number cube was rolled 100
times? OR What is the probability of
Probability = number of times action occurs
Total number or number of 100
possible outcomes
Experimental Probability
=16 + 19
100
=number of times 3 or 6 is rolled
= 35
100
Method) add the two or more events mentioned in the question
Probability
of “all but”
What is the [probability of rolling anything but a 3?
Method 1) Add up all of the events mentioned in the graphic except the
event mentioned in the question
Probability = number of times all other action occurs =
14 + 13 + 19 + 21 + 17
Total number or number of possible outcomes
100
Experimental Probability
= 84
100
Method 2) Probability = total number - number of times specific action occurs
Total number or number of possible outcomes
total number – occurrence discussed =
100
= 100 -16=
100
84
100
Probability
of one event
using a
different
number than
the total
possible
outcomes
provided in
the graphic
or original
information
provided
The graph shows the results of an experiment in which a number cube was
rolled 100 times. Find the experimental probability of rolling a 3 for this
experiment, if the dice was rolled 550 times.
Probability = number of times action occurs
Total number or number of possible outcomes
Step 1) set this proportion equal to the new proportion& solve for x (like you
solve 2 step equations)
16
100
=
x
550
Step 2) Cross Multiply
16 x 550 =100(x)
8800 = 100 x
Step 3) solve for x (using your equation notes)
divide both sides by the coefficient to get the x alone
8800 = 100 x
100
100
x = 88
Step 4) Label your answer = The experimental probability of rolling a 3 if the
dice was rolled 550 times is 88 times.
Vocabulary
Experimental Probability - is found using frequencies obtained in an experiment or
game.
Ex the likelihood of rolling a 6 in this experiment =
17
100
Theoretical probability is the expected probability of an event occurring.
17
Ex the likelihood of rolling a 6 in theory is =
100