Unit 11
Day 2
Histograms and Stem-and-Leaf Plots
Warm Up! The number of text messages sent on one day by different students are shown below. Make a
frequency table and histogram that represents the data. Be sure to label the graph and your axes.
17 3 1 30
27 2 0
11
7
1
5
2
39
22 13 2 0 21 1 29 40
Histogram Shape (data distribution)
After collecting class data, draw a rough sketch of each graph. Then, describe the distribution according to
the shape of the histogram:
Siblings
Summer Trips
Shape: ______________________________
Shape: _______________________________
Social Networks
Shape: ____________________________
Stem-and-leaf plot:
_______________________________________________________________________________________________________
Example 1:
The numbers of students in 14 math classes at Hinsdale Central are given below. Use the data to make a stem-andleaf plot and describe the shape of the distribution.
24, 14, 12, 25, 32, 18, 23, 24, 9, 18, 34, 28, 24, 27
Math Class Size
Stem
Leaf
Key: _________________________
Example 2:
The ages of professional XBOX players are given below. Use the data to make a stem-and-leaf plot and describe the
shape of the distribution.
12, 23, 21, 18, 22, 32, 38, 28, 15, 36, 20, 21
Ages of Professional XBOX Players
Partner Practice!
Included below is the stem-and-leaf plot that illustrates the number of miles driven by each new car parked in a lot.
1. How many cars have over 50 miles?
2. How many cars have less than 50 miles?
3. How many total cars were checked for mileage?
4. What is the most miles on a car? Lowest mileage?
One more example!
Heading into the NHL playoffs, teams are ranked by their division using point values (from their # of wins and ties)
to determine which teams from each division will make the playoffs. Use the data to make a back-to-back stemand-leaf plot. Source: www.NHL.com
Western Conference: 100, 99, 95, 92, 90, 89, 62, 56, 109, 101, 97, 109, 104, 102
Eastern Conference: 99, 98, 91, 89, 84, 78, 71, 68, 54, 113, 101, 100, 110, 108
Point totals of NHL Teams Leading into Playoffs
Western
Eastern
Key:
Using the same information described above, make a frequency chart and histogram of the Eastern Division teams
to describe the shape of the distribution. Be sure to label the graph and your axes.
Assuming only the top six teams from each division make the playoffs, what is the cutoff score for the Eastern
Division?