7-1. IWBAT organize and interpret data in frequency tables, stem-and-leaf plots, and line plots.

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1 IWBAT organize and interpret data in frequency tables, stem-and-leaf plots, and line plots.

2 Vocabulary frequency table cumulative frequency stem-and-leaf plot line plot

3 WRITE: A frequency table is a way to organize data into categories or groups. By including a cumulative frequency column in your table, you can keep a running total of the frequencies in each category. Remember! The frequency of a data value is the number of times it occurs.

4 EX 1: Organizing and Interpreting Data in a Frequency Table 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 Step 1: Choose a scale that includes all of the data values. Then separate the scale into equal intervals. February Temperatures in 20 Cities Average Highs Frequency Cumulative Frequency

5 EX 1 Continued 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 Step 2: Find the number of data values in each interval. Write these numbers in the Frequency column. February Temperatures in 20 Cities Average Highs Frequency Cumulative Frequency

6 EX 1 Continued 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 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 Cities Average Highs Frequency Cumulative Frequency cities had average high temperature below 59 degrees

7 WRITE: A stem-and-leaf plot uses the digits of each number to organize and display a set of data. Each leaf on the plot represents the right-hand digit in a data value, and each stem represents left-hand digits. Stems Leaves Key: 2 7 means 27

8 EX 2: Organizing and Interpreting Data in a Stem-and- Leaf Plot 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 Step 1: Order the data from least to greatest. Since the data values range from 12 to 40, use tens digits for the stems and ones digits for the leaves.

9 EX 2 Continued 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 Step 2: List the stems from least to greatest on the plot. The stems are the tens digits. Stems Leaves

10 EX 2 Continued 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 Step 3: List the leaves for each stem from least to greatest. The stems are the tens digits. Stems 1 Leaves The leaves are the ones digits

11 EX 2 Continued Step 4: Add a key and a title. The stems are the tens digits. Key: 2 1 means 21. Number of Years Coached Stems Leaves The leaves are the ones digits. 11 coaches coached fewer than 25 years.

12 EX 3: Organizing and Interpreting Data in a Line Plot Make a line plot of the data. How many hours per day did Morgan babysit most often? Number of Babysitting Hours in July M T W Th F S Su Wk Wk Wk Wk

13 EX 3 Continued Make a line plot of the data. How many hours per day did Morgan babysit most often? Step 1: The data values range from 0 to 8. Draw a number line that includes this range

14 EX 3 Continued Make a line plot of the data. How many hours per day did Morgan babysit most often? Step 2: Put an X above the number on the number line that corresponds to the number of babysitting hours in July. X X X X The greatest number of X s appear above the number 6. This means that Morgan babysat most often for 6 hours.

Frequency Tables, Stem-and-Leaf Plots, and Line Plots

LESSON 7-1 Frequency Tables, Stem-and-Leaf Plots, and Line Plots Lesson Objectives Organize and interpret data in frequency tables, stem-and-leaf plots, and line plots Vocabulary frequency table (p. 80)