Double Line Graphs
9-10
- Describe the change in T-shirt stock
from April to August. - When was the total stock of T-shirts
and sweatshirts the greatest? When
was the total stock the least? - Why might stocks of both T-shirts and sweatshirts increase
greatly from August to September?
Use the double line graph above.
- Describe the change in sweatshirt
stock between February and May. - 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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