7-1 frequency tables, stem-and-leaf plots, and line plots learn to organize and interpret data in...
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7-1 Frequency Tables, Stem-and-Leaf Plots, and Line Plots
Learn to organize and interpret data in frequency tables, stem-and-leaf plots, and line plots.
7-1 Frequency Tables, Stem-and-Leaf Plots, and Line Plots
The list shows the average high temperatures for 20 cities on one February day. Make a cumulative frequency table of the data. How many cities had average high temperature below 59 degrees?
69, 66, 65, 51, 50, 50, 44, 41, 38, 32, 32, 28, 20, 18, 12, 8, 8, 4, 2, 2
Additional Example 1: Organizing and Interpreting Data in a Frequency Table
February Temperatures in 20 CitiesAverage
HighsFrequency
Cumulative Frequency
Step 1: Look at the range to choose equal intervals for the data.
0–20
21-40
41-60
61-80
7-1 Frequency Tables, Stem-and-Leaf Plots, and Line Plots
The list shows the average high temperatures for 20 cities on one February day. Make a cumulative frequency table of the data. How many cities had average high temperature below 59 degrees?
69, 66, 65, 51, 50, 50, 44, 41, 38, 32, 32, 28, 20, 18, 12, 8, 8, 4, 2, 2
Additional Example 1 Continued
Step 2: Find the number of data values in each interval. Write these numbers in the “Frequency” column.
February Temperatures in 20 CitiesAverage
HighsFrequency
Cumulative Frequency
8
4
5
3
0–20
21-40
41-60
61-80
7-1 Frequency Tables, Stem-and-Leaf Plots, and Line Plots
The list shows the average high temperatures for 20 cities on one February day. Make a cumulative frequency table of the data. How many cities had average high temperature below 59 degrees?
69, 66, 65, 51, 50, 50, 44, 41, 38, 32, 32, 28, 20, 18, 12, 8, 8, 4, 2, 2
Additional Example 1 Continued
Step 3: Find the cumulative frequency for each row by adding all the frequency values that are above or in that row.
February Temperatures in 20 CitiesAverage
HighsFrequency
Cumulative Frequency
0–20
21-40
41–60
61-80
8
4
5
3
8
12
17
20
17 cities had average high temperature below 59 degrees.
7-1 Frequency Tables, Stem-and-Leaf Plots, and Line Plots
The data shows the number of years coached by the top 15 coaches in the all-time NFL coaching victories. Make a stem-and-leaf plot of the data. Then find the number of coaches who coached fewer than 25 years.
33, 40, 29, 33, 21, 23, 23, 22, 19, 21, 18, 23, 15, 15, 15
Stem and Leaf Plots
Step 1: Find the least data value and the greatest data value. Since the data values range from 15 to 40, use tends digits for stems and ones digits for the leaves.
7-1 Frequency Tables, Stem-and-Leaf Plots, and Line Plots
Additional Example 2 Continued
Step 2: List the stems from least to greatest on the plot.
Stems Leaves
1
2
3
4
The stems are the tens digits.
The data shows the number of years coached by the top 15 coaches in the all-time NFL coaching victories. Make a stem-and-leaf plot of the data. Then find the number of coaches who coached fewer than 25 years.
33, 40, 29, 33, 23, 22, 20, 21, 18, 23, 17, 15, 15, 12, 17
7-1 Frequency Tables, Stem-and-Leaf Plots, and Line Plots
Additional Example 2 Continued
Step 3: List the leaves for each stem from least to greatest.
Stems Leaves
1
2
3
4
The stems are the tens digits.
5 5 5 8 91 1 2 3 3 93 3
0
The leaves are the ones digits.
The data shows the number of years coached by the top 15 coaches in the all-time NFL coaching victories. Make a stem-and-leaf plot of the data. Then find the number of coaches who coached fewer than 25 years.
33, 40, 29, 33, 23, 22, 20, 21, 18, 23, 17, 15, 15, 12, 17
3
7-1 Frequency Tables, Stem-and-Leaf Plots, and Line Plots
Additional Example 2 Continued
Step 4: Add a key and a title The stems area the tens digits. The leaves are the ones digits.
The stems are the tens digits.
The leaves are the ones digits.
Number of Years Coached
Key: 2 | 1 means 21.
11 coaches coached fewer than 25 years.
7-1 Frequency Tables, Stem-and-Leaf Plots, and Line Plots
Make a line plot of the data. How many hours per day did Morgan babysit most often?
Additional Example 3: Organizing and Interpreting Data in a Line Plot
0633484Wk 4
2165860Wk 3
8607772Wk 2
2856460Wk 1
SuSFThWTM
Number of Babysitting Hours in July
7-1 Frequency Tables, Stem-and-Leaf Plots, and Line Plots
Make a line plot of the data. How many hours per day did Morgan babysit most often?
Additional Example 3 Continued
Step 1: The data values range from 0 to 8. Draw a number line that includes this range.
0 1 2 3 4 5 6 7 8
7-1 Frequency Tables, Stem-and-Leaf Plots, and Line Plots
Make a line plot of the data. How many hours per day did Morgan babysit most often?
Additional Example 3 Continued
Step 2: Put an X above the number on the number line that corresponds to the number of hours Morgan babysat each day.
0 1 2 3 4 5 6 7 8
XXXX
X
XXX XX
XXX XX
XXXXXX
XXX
XXXX
The greatest number of X’s appear above the number 6. This means that Morgan babysat most often for 6 hours.