7-6 Line Graphs Warm Up Problem of the Day Lesson Presentation Course 2

Course 2 7-6 Line Graphs Warm Up 1. What is the x-coordinate of the point (2, 3)? 2. To plot the point (3, 7) you would move right ___ units then up ___ units. 3. To plot the point (4, –5) would you move left or right first? 2 3 7 right

7-6 Line Graphs Problem of the Day Find three mistakes on the graph. Course 2 7-6 Line Graphs Problem of the Day Find three mistakes on the graph. Trucks Sold The line does not connect all the points. 8 7 6 4 3 2 The intervals on the vertical scale are not equal. Number of trucks sold Tuesday shows sales of 6.5 trucks (not possible). Mon Tues Wed Thurs Fri Days of week

7-6 Line Graphs Learn to display and analyze data in line graphs. Course 2 7-6 Line Graphs Learn to display and analyze data in line graphs.

Course 2 7-6 Line Graphs Vocabulary line graph double-line graph

Course 2 7-6 Line Graphs You can use a line graph to show how data changes over a period of time. A line graph uses line segments to connect data points. The result is a visual record of change.

Additional Example 1: Making a Line Graph Course 2 7-6 Line Graphs Additional Example 1: Making a Line Graph Make a line graph of the data in the table. During which 2-hour period did the temperature change the most? Time 11 A.M. 1 P.M. 3 P.M. 5 P.M. Temperature 80°F 88°F 92°F 89°F

Additional Example 1 Continued Course 2 7-6 Line Graphs Additional Example 1 Continued Time 11 A.M. 1 P.M. 3 P.M. 5 P.M. Temperature 80°F 88°F 92°F 89°F Step 1: Determine the scale and interval for each axis. Place units of time on the horizontal axis. 95 °F 90 °F 85 °F 80 °F 75 °F 11 AM 1 PM 3 PM 5 PM

Additional Example 1 Continued Course 2 7-6 Line Graphs Additional Example 1 Continued Time 11 A.M. 1 P.M. 3 P.M. 5 P.M. Temperature 80°F 88°F 92°F 89°F Step 2: Plot a point for each pair of values. Connect the points using line segments. 95 °F 90 °F 85 °F 80 °F 75 °F To plot each point, start at zero. Move right for the time and up for the degree. Helpful Hint 11 AM 1 PM 3 PM 5 PM

Additional Example 1 Continued Course 2 7-6 Line Graphs Additional Example 1 Continued Time 11 A.M. 1 P.M. 3 P.M. 5 P.M. Temperature 80°F 88°F 92°F 89°F Step 3: Label the axes and give the graph a title. Temperatures on a Given Day 11 AM 1 PM 3 PM 5 PM 95 °F 90 °F 85 °F 80 °F 75 °F Temperature °F Time

Additional Example 1 Continued Course 2 7-6 Line Graphs Additional Example 1 Continued The temperature changed the most between 11 A.M. and 1 P.M. 11 AM 1 PM 3 PM 5 PM 95 °F 90 °F 85 °F 80 °F 75 °F Time Temperature °F Temperatures on a Given Day

7-6 Line Graphs Check It Out: Example 1 Month Jan Feb Mar Apr Course 2 7-6 Line Graphs Check It Out: Example 1 Month Jan Feb Mar Apr Homes Sold 8 6 15 23 Step 1: Determine the scale and interval for each axis. Place units of time on the horizontal axis. 25 20 15 10 5 Jan Feb Mar Apr

Check It Out: Example 1 Continued Course 2 7-6 Line Graphs Check It Out: Example 1 Continued Month Jan Feb Mar Apr Homes Sold 8 6 15 23 Step 2: Plot a point for each pair of values. Connect the points using line segments. 25 20 15 10 5 Jan Feb Mar Apr

Check It Out: Example 1 Continued Course 2 7-6 Line Graphs Check It Out: Example 1 Continued Month Jan Feb Mar Apr Homes Sold 8 6 15 23 Step 3: Label the axes and give the graph a title. Homes Sold 25 20 15 10 5 Number of Homes Sold Jan Feb Mar Apr Month

Check It Out: Example 1 Continued Course 2 7-6 Line Graphs Check It Out: Example 1 Continued Between February and March showed the greatest increase in number of homes sold. Homes Sold 25 20 15 10 5 Number of Homes Sold Jan Feb Mar Apr Month

Course 2 7-6 Line Graphs You can use a line graph to estimate values between data points.

Additional Example 2: Using a Line Graph to Estimate Data Course 2 7-6 Line Graphs Additional Example 2: Using a Line Graph to Estimate Data Use the Florida population graph to estimate the population of Florida in 1950. To estimate the population in 1950, find the point on the line between 1940 and 1960 that corresponds to 1950. The graph shows about 3.5 million people.

7-6 Line Graphs Check It Out: Example 2 Course 2 7-6 Line Graphs Check It Out: Example 2 Use the Florida Population graph to estimate the population of Florida in 1970. To estimate the population in 1970, find the point on the line between 1960 and 1980 that corresponds to 1970. The graph shows about 7.5 million people.

Course 2 7-6 Line Graphs A double-line graph shows change over time for two sets of data.

Additional Example 3: Making a Double-Line Graph Course 2 7-6 Line Graphs Additional Example 3: Making a Double-Line Graph The table shows stock prices for two stocks in one week. Make a double-line graph of the data. Stock A $10 $9 $11 $10 $8 Stock B $6 $12 $8 $14 $14 Mon Tue Wed Thu Fri

Additional Example 3 Continued Course 2 7-6 Line Graphs Additional Example 3 Continued Stock A $10 $9 $11 $10 $8 Stock B $6 $12 $8 $14 $14 Mon Tue Wed Thu Fri Stock Prices 15 12 9 6 3 Mon Tue Wed Thu Fri Plot a point for Stock A for each day of the week. Price ($) Then, using a different color, plot a point for Stock B for each day of the week. Day

Additional Example 3 Continued Course 2 7-6 Line Graphs Additional Example 3 Continued Stock A $10 $9 $11 $10 $8 Stock B $6 $12 $8 $14 $14 Mon Tue Wed Thu Fri Stock Prices 15 12 9 6 3 Mon Tue Wed Thu Fri Connect the points. Price ($) Day

Additional Example 3 Continued Course 2 7-6 Line Graphs Additional Example 3 Continued Stock A $10 $9 $11 $10 $8 Stock B $6 $12 $8 $14 $14 Mon Tue Wed Thu Fri Stock Prices 15 12 9 6 3 Mon Tue Wed Thu Fri Make a key to show what each line represents. Price ($) Stock A Stock B Day

7-6 Line Graphs Check It Out: Example 3 Mon Tue Wed Thu Fri Course 2 7-6 Line Graphs Check It Out: Example 3 Stock A $8 $10 $6 $4 $8 Stock B $4 $14 $12 $14 $12 Mon Tue Wed Thu Fri Stock Prices 15 12 9 6 3 Mon Tue Wed Thu Fri Plot a point for Stock A for each day of the week. Price ($) Then, using a different color, plot a point for Stock B for each day of the week. Day

Check It Out: Example 3 Continued Course 2 7-6 Line Graphs Check It Out: Example 3 Continued Stock A $8 $10 $6 $4 $8 Stock B $4 $14 $12 $14 $12 Mon Tue Wed Thu Fri Stock Prices 15 12 9 6 3 Mon Tue Wed Thu Fri Connect the points. Price ($) Day

Check It Out: Example 3 Continued Course 2 7-6 Line Graphs Check It Out: Example 3 Continued Stock A $8 $10 $6 $4 $8 Stock B $4 $14 $12 $14 $12 Mon Tue Wed Thu Fri Stock Prices 15 12 9 6 3 Mon Tue Wed Thu Fri Make a key to show what each line represents. Price ($) Stock A Stock B Day

Hot Air Balloon Heights Course 2 7-6 Line Graphs Lesson Quiz: Part I Make a double line graph of the data. Hot Air Balloon Heights Time (A.M.) Balloon 1 Balloon 2 6:00 0 0 6:15 150 175 6:30 250 275 6:45 350 375 7:00 350 400 7:15 250 275

Lesson Quiz: Part I Continued Course 2 7-6 Line Graphs Lesson Quiz: Part I Continued

7-6 Line Graphs Lesson Quiz: Part 2 Course 2 7-6 Line Graphs Lesson Quiz: Part 2 2. Use the graph that you made in Exercise 1 to estimate the height of each balloon between 6:30 A.M. and 6:45 A.M. 300 ft: 325 ft