COMPARING PROBABILITIES
(Experimental versus Theoretical)
Example 1:
Toss a coin 10 times and record the
number of heads that turn up.
a)
Determine the experimental probability of turning
up heads in a coin toss.
b)
Determine the theoretical probability of turning up
heads in a coin toss.
c)
Trial
#
1
2
3
4
5
6
7
8
9
10
Heads
()
If you tossed the coin several more times, would you expect
the experimental probability to increase or decrease?
The theoretical and experimental probabilities of an event are not necessarily the same.
As the number of trials increases, the experimental
probability gets closer to the theoretical probability.
Example 2:
A spinner is used to simulate the results of rolling a die 20 times.
The results are shown in the table.
Outcome
1
2
3
4
5
6
b)
Frequency
3
2
6
2
4
3
a)
Determine the probability of each outcome.
P(1) =
P(2) =
P(3) =
P(4) =
P(5) =
P(6) =
Are the probabilities calculated in part a) experimental or theoretical? Explain.
Unit 7 Lesson 3
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