Page 421 - Algebra 1

L E S S O N Displaying Data in Stem-and-Leaf Plots and
62
Histograms
Warm Up
New Concepts
1. Vocabulary The sum of the values in a data set divided by the number of
(48)
data values gives the . A mean B median
C mode Find the mean, median, mode, and range.
D range
2. 5, 3, 7, 6, 2, 4, 5, 8 (48)
3. 12, 15, 20, 16, 14, 13 (48)
A stem-and-leaf plot is a data display that uses some digits as “stems” and others as “leaves”. The “stems” have a greater place value than the “leaves.” Stem-and-leaf plots are helpful in organizing data and displaying it to show the distribution of values.
stem 2 3 leaf
The digits other than the last digit are the stem. The last digit of a number is the leaf.
Making a Stem-and-Leaf Plot
The high temperatures in degrees Fahrenheit for April 2007 in New Orleans, Louisiana, are shown. Create a stem-and-leaf plot of the data.
70, 83, 84, 77, 66, 67, 53, 55, 64, 69, 82, 78, 80, 81, 66, 71, 75, 76, 80, 78, 78, 81, 83, 83, 82, 81, 80, 85, 87, 87
SOLUTION
Step1: Therearetwoplacevaluesineachtemperatureinthedataset, tens and ones. Organize the data by each tens value. Write each place-value group in ascending order. Include any values that repeat.
50’s: 53, 55
60’s: 64, 66, 66, 67, 69
70’s: 70, 71, 75, 76, 77, 78, 78, 78
80’s: 80, 80, 80, 81, 81, 81, 82, 82, 83, 83, 83, 84, 85, 87, 87
Example
1
Step 2: Use the tens digit of each group as the stem of a row on a stem-and-leaf plot. Write each ones digit as the leaf
for the corresponding tens digit.
Step3: Createakeytoshowhowto read each entry in the plot.
High Temperatures (°F) April 2007 for New Orleans, LA
Math Language
All stem-and-leaf plots include a key to indicate how to read each stem and leaf. Place-value information and units are indicated.
Stem
5 6 7 8
Leaves
3, 5
4, 6, 6, 7, 9
0, 1, 5, 6, 7, 8, 8, 8
0, 0, 0, 1, 1, 1, 2, 2, 3, 3, 3, 4, 5, 7, 7
406 Saxon Algebra 1
8⎥ 5 = 85°F
Key: 5 3 = 53°F