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General Addition Rule
Topic 15: Conditional Probability, Expected Value, and Strategy
in
Sports
CCLS
standards
Interpreting Categorical and Quantitative Data
Summarize, represent, and interpret data on two categorical
and quantitative variables.
 Summarize categorical data for two categories in two-way
frequency tables. Interpret relative frequencies in the
content of the data (including joint, marginal, and
conditional relative frequencies). Recognize possible
associations and trends in the data.
Conditional Probability and the Rules of Probability
Understand independence and conditional probability and
use them to interpret data
 Construct and interpret two-way frequency tables of data
when two categories are associated with each object being
classified. Use the two-way table as a sample space to
decide if events are independent and to approximate
conditional probabilities.
Use the rules of probability to compute probabilities of
compound events in a uniform probability model
 Apply the Addition Rule, P(A or B) = P(A) + P(B) – P(A and
B), and interpret the answer in terms of the model.
Homework 2
General Addition Rule
Name: ____________________________
Probability & Statistics
Date: _____
CW/HW#70
1. In the 2010 – 2011 regular season, fans at Chicago Bulls games won a
free Big Mac if the Bulls scored at least 100 points. The two-way
table below summarizes the outcomes of each of the Bulls’ 41 home
games and whether or not the fans got a free Big Mac.
Suppose that we randomly select one Bulls home game in 2010 – 2011.
a. What is the probability that a fan at the game witnessed a win and
got a free Big Mac?
b. Interpret the probability that you calculated in part (a).
If a fan were to attend lots and lots of Bulls home games, then
the Bulls would ____ and the fan would win a ______ about
_____% of the time.
c. What is the probability that a fan at the game witnessed a win or
got a free Big Mac?
d. What is the probability that a fan at the game neither witnessed a
win nor got a free Big Mac?
General Addition Rule
2. In the 1953 season, pitcher Robin Roberts of the Philadelphia Phillies
was one of the best pitchers in baseball. He started 40 games and
had a quality start (QS) in 27 of them. A quality start for a pitcher is
any game where he throws at least 6 innings and gives up at most 3
earned runs. The table below shows the Phillies’ outcome for each of
his 40 starts and whether or not Roberts had a quality start.
a. Create a two-way table to summarize the results of Roberts’s
starts.
b. If you were to randomly select one of the games that Roberts
started, what is the probability that he had a quality start or that
his team won the game?