7th Grade Math

(Marvins-Underground-K-12) #1

Predictions


PART A BCDE


3


Multi-Part
Lesson

Get ConnectED

F

GLE 0706.5.5
Understand and apply basic
concepts of probability.
SPI 0706.5.4 Use theoretical
probability to make
predictions. Also addresses
GLE 0706.1.4.

458 Probability and Predictions

Main Idea
Find and compare
experimental and
theoretical
probabilities.

Vocabulary
theoretical probability
experimental probability

Theoretical and Experimental


Probability


Follow the steps to
determine how many times doubles
are expected to turn up when two
number cubes are rolled.

Step 1 Use the table to help you find the expected number of
times doubles should turn up when rolling two number
cubes 36 times. The top row represents one number cube,
and the left column represents the other number cube.

1 2 3 4 5 6

123456
1, 1
2, 1
3, 1
4, 1
5, 1
6, 1

1, 2
2, 2
3, 2
4, 2
5, 2
6, 2

1, 3
2, 3
3, 3
4, 3
5, 3
6, 3

1, 4
2, 4
3, 4
4, 4
5, 4
6, 4

1, 5
2, 5
3, 5
4, 5
5, 5
6, 5

1, 6
2, 6
3, 6
4, 6
5, 6
6, 6

Step 2 Roll two number cubes 36 times. Record the number of
times doubles turn up.


  1. Compare the number of times you expected to roll doubles with
    the number of times you actually rolled doubles.

  2. Write the probability of rolling doubles out of 36 rolls using the
    number of times you expected to roll doubles from Step 1. Then
    write the probability of rolling doubles out of 36 rolls using the
    number of times you actually rolled doubles from Step 2.


Theoretical probability is based on what should happen when
conducting a probability experiment. This is the probability you have
been using since Lesson 1A. Experimental probability is based on
what actually occurred during such an experiment.

Theoretical Probability

_ 366 6 rolls should occur


Experimental Probability

_ 36 n n rolls actually occurred


The theoretical probability and the experimental probability of an
event may or may not be the same. As the number of times an
experiment is conducted increases, the theoretical probability and the
experimental probability should become closer in value.

458_463_C08_L3_895130.indd 458 12/29/09 1:28 PM

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