McGraw Hill Glencoe Algebra 2, 2012
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McGraw Hill Glencoe Algebra 2, 2012 View details
5. Adding Probabilities
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Exercise 1 Page P15

Practice makes perfect
a We want to find the probability of landing on each color of the spinner. The experimental probability is a quotient.
P(E)=number of favorable trials/number of trials

For the different colors the number of favorable trials is given in the table. The total number of trials is the sum of these individual frequencies. 6+ 7+ 9+ 12+ 5+ 11= 50 Let's find these quotients and add a column to the table as asked.

Color Frequency Experimental Probability
red 6 6/50= 0.12
blue 7 7/50= 0.14
yellow 9 9/50= 0.18
orange 12 12/50= 0.24
purple 5 5/50= 0.1
green 11 11/50= 0.22
b Let's now plot these values on a bar graph. The height of the bars should be proportional to the probabilities we found in part A.
c Since the spinner has sections of equal size, let's assume that landing on different colors is equally likely. Under this assumption, the theoretical probability can be calculated as a quotient.

P(E)=number of favorable outcomes/number of possible outcomes In this case, the number of possible outcomes is the number of colors, so it is 6. For calculating the probability of the spinner landing on each color, the number of favorable outcomes is 1. Let's add these theoretical probabilities to the table.

Color Frequency Experimetal Probability Theoretical Probability
red 6 0.12 1/6= 0.16
blue 7 0.14 1/6= 0.16
yellow 9 0.18 1/6= 0.16
orange 12 0.24 1/6= 0.16
purple 5 0.1 1/6= 0.16
green 11 0.22 1/6= 0.16
d Let's now graph the theoretical probability. The height of the bars should be proportional to the probabilities we found in part C.
e The bars on the graph of the theoretical probability are of equal height. This is the consequence of our assumption, that landing on different colors is equally likely.

The bars on the graph of the experimental probabilities are not of equal height. This indicates that the assumption of the uniform distribution may not be justified.