6th Grade Math Textbook, Progress

Double Line Graphs

9-10

1. Describe the change in T-shirt stock
   from April to August.


2. When was the total stock of T-shirts
   and sweatshirts the greatest? When
   was the total stock the least?


3. Why might stocks of both T-shirts and sweatshirts increase
   greatly from August to September?

Use the double line graph above.

2. Describe the change in sweatshirt
   stock between February and May.


3. When was the difference between the
   stock of T-shirts and sweatshirts the
   greatest? When was it the least?

Stock at Sam’s Shirts

Month T-Shirts Sweatshirts

Jan. 275 225

Feb. 375 175

Mar. 350 200

Apr. 450 250

May 410 310

June 400 300

July 350 250

Aug. 300 175

Sept. 500 260

0

50

100

Key: T-shirts

Sweatshirts

150

200

250

300

350

400

450

500

Number in Stock

Month

Jan. Feb.Mar. Apr. May June July Aug. Sept.

Stock at Sam's Shirts

Sam’s Shirts sells T-shirts and sweatshirts.

The owner recorded in a table how many

T-shirts and sweatshirts were in stock during

a 9-month period. He then displayed the

results in a double line graph.

A double line graph compares two sets of

data over time. The data sets are graphed

separately on the same grid. The key shows

which line graph represents each data set.

To make a double line graph:

• Draw horizontal and vertical
  axes on grid paper.


• Choose an appropriate scale for
  both sets of data.


• Label both axes. On the vertical
  axis, mark equal intervals
  beginning with 0. On the horizontal
  axis, write the categories.


• Choose two different colors and
  make a key to show what each
  color represents.


• Plot a point for each data item.
  Join the points with line segments.


• Write a title for the graph.

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