Here are step-by-step directions for finding the mean, median, mode, and range of a data set: 1. List all data values from the data set. 2. To find the median, arrange the data values in numerical order from lowest to highest. 3. If there is an odd number of values, the median is the middle number. If there is an even number of values, the median is the average of the two middle numbers. 4. To find the mode, identify the data value(s) that occur most frequently. There may be more than one mode. 5. To find the mean, add all the data values and divide the sum by the total number of

1. Course 3, Lesson 9-4
Use the make a graph strategy to solve the problems.
For Exercises 1 and 2, use the bar
graph at the right.
1. How many students are in the eighth
grade?
2. What percentage of students does
not play sports?
3. The graph shows the number of
points scored for the first seven
weeks of the football season.
What type of association does
the data show?

2. Course 3, Lesson 9-4
ANSWERS
1. 219 students
2. 40.6%
3. no association

3. HOW are patterns used
when comparing two quantities?
Statistics and Probability
Course 3, Lesson 9-4

4. Course 3, Lesson 9-4 Common Core State Standards © Copyright 2010. National Governors Association Center for
Best Practices and Council of Chief State School Officers. All rights reserved.
Statistics and Probability
• Preparation for S.ID.1
Represent data with plots on the real number line (dot plots,
histograms, and box plots).
• Preparation for S.ID.2
Use statistics appropriate to the shape of the data distribution to
compare center (median, mean) and spread (interquartile range,
standard deviation) of two or more different data sets.

5. Course 3, Lesson 9-4 Common Core State Standards © Copyright 2010. National Governors Association Center for
Best Practices and Council of Chief State School Officers. All rights reserved.
Statistics and Probability
Mathematical Practices
1 Make sense of problems and persevere in solving them.
2 Reason abstractly and quantitatively.
3 Construct viable arguments and critique the reasoning of others.
4 Model with mathematics.
7 Look for and make use of structure.

6. To
• describe univariate data using
measures of center,
• measure quantitative data using
a five-number summary
Course 3, Lesson 9-4 .
Statistics and Probability

7. • univariate data
• quantitative data
• five-number summary
Course 3, Lesson 9-4
Statistics and Probability

8. 1
Need Another Example?
2
3
4
Step-by-Step Example
1. The ages, in years, of the people seated in one row of a movie theater
are 16, 15, 24, 33, 30, 56, 19, and 19. Find the mean, median, mode, and
range of the data set.
Mean
The mode is 19, since it is the number that occurs most often.
Arrange in order from least to greatest.Median 15, 16, 19, 19, 24, 30, 33, 56
Mode
56 – 15 = 41Range

9. Answer
Need Another Example?
The ages, in years, of the actors in a play are
5, 16, 32, 15, 26, and 32. Find the mean, median,
mode, and range of the data set.
mean: 21; median: 21; mode: 32; range: 27

10. 1
Need Another Example?
2
3
5
Step-by-Step Example
2. The data for daily average temperatures for
15 days in May are shown in the table.
a. Find the five-number summary of the data.
b. Draw a box plot of the data.
b.
68 69 70 71 72 72 73 74 75 75 75 75 76 76 76
minimum
Draw the box plot and assign a title to the graph.
Daily Temperatures
a. Write the data from least to greatest.
first quartile median third quartile maximum
Draw a number line that includes the least and greatest numbers in the data.
Mark the minimum and maximum values, the median, and the first and third
quartiles above the number line.
4

11. Answer
Need Another Example?
Find the five-number
summary of the data.
Draw a box plot of
the data.
minimum: 39.1; Q 1 : 59.25; median: 74.1;
Q 3 : 81.4; maximum: 95.5

12. How did what you learned
today help you answer the
How are patterns used
when comparing two quantities?
Course 3, Lesson 9-4
GeometryStatistics and Probability

13. How did what you learned
today help you answer the
How are patterns used
when comparing two quantities?
Course 3, Lesson 9-4
GeometryStatistics and Probability
Sample answers:
• You can find the five-number summary of a set of
univariate data.
• Using the five-number summary, you can construct and
analyze a box plot of the data.

14. Write a set of directions for
finding mean, median, mode,
and range for a data set.
Course 3, Lesson 9-4
Ratios and Proportional RelationshipsFunctionsStatistics and Probability