1.6 Tables and Graphs
What you should learn
GOAL
GOAL
1
Use tables to organize data.
2
Use graphs to organize real-life data, such
as the amounts of various foods consumed
(Example 2).
Why you should learn it
To help you see relationships among real-life data,
such as the average cost of making a movie.
1.6 Tables and Graphs
GOAL
1
USING TABLES TO ORGANIZE DATA
Remember: A table is just one way to organize data.
We need to organize it to make it easier to understand.
EXAMPLE 1
Extra Example 1
The data in the table represents the number of worldwide
shipments of personal computers, in millions. During
which 2-year period did the number of shipments
increase the most?
PC Shipments (millions)
Year ’90 ’92 ’94 ’96
PCs
Solution:
Change
’98
23.7 32.4 47.9 70.8 98.4
---- 8.7 15.5 22.9 27.6
Find the difference in each 2-year period.
The greatest increase in shipments
occurred from 1996-1998.
1.6 Tables and Graphs
GOAL
2
USING GRAPHS TO ORGANIZE DATA
BAR GRAPHS—The bars may be either vertical or
horizontal.
LINE GRAPHS—Connect the data points with
straight lines; do not draw curves.
EXAMPLE 2
Extra Example 2
A graph for the data
in Extra Example 1 is
shown. Is the graph
misleading? Explain.
PC Shipments (millions)
Year ’90 ’92 ’94 ’96
’98
PCs 23.7 32.4 47.9 70.8 98.4
PC Shipments
milliions
100
The bar graph is
not misleading
since the vertical
scale is
consistent.
75
50
25
0
1990
1992
1994
Year
1996
1998
Drawing Graphs
All graphs need:
1. Title
2. Axis labels
3. Appropriate scale
Does it go beyond the largest number?
Does it show the differences in data?
4. Consistent scale
5. Neatness
Checkpoint
The data in the table represents the number of households
in the U.S. in millions.
Year
’60
’70
No.
52.8
63.4
’80
’90
’00
80.8 93.3 103.2
a. During which 10-year period did the number of
households increase the most?
1970 to 1980
b. Draw a bar graph to represent the data.
Checkpoint (cont.)
Year ’60
No. 52.8
’70
63.4
’80 ’90
’00
80.8 93.3 103.2
U.S. Households
TITLE
SCALE
Number (millions)
120
100
80
60
40
20
0
1960
1970
1980
1990
Year
LABELS
EXAMPLE 3
2000
SCALE
Extra Example 3
The data in the table represents the number of people over
age 65 in the U.S. in millions.
’60
Year
No. 17.4
a. Draw a line graph.
’70
21.4
’80
’90
27.8 34.3
’00
39.0
U.S. Population Over Age 65
Number (millions)
50
40
30
20
10
0
’60
’70
’80
Year
’90
’00
Extra Example 3 (cont.)
b. During which 10-yr period was there the least increase?
Year
’60
’70
No.
17.4
21.4
’80
’90
27.8 34.3
’00
39.0
Think: How
does the bar
graph show the
answer to this
question?
U.S. Population Over Age 65
50
Number (millions)
Answer: from
1960 – 1970.
40
30
20
10
0
’60
’70
’80
Year
’90
’00
The steeper the
line, the greater
the difference
between the
points.
Checkpoint
a. Draw a line graph
for the data in Extra
Example 1.
PC Shipments (millions)
Year ’90 ’92 ’94 ’96
’98
PCs 23.7 32.4 47.9 70.8 98.4
Number (millions)
PC Shipments
120
100
80
60
40
20
0
1990
1992
1994
1996
1998
Year
b. During which two-year period did the number of
shipments increase the least? 1990-1992
QUESTIONS?