To compare sets of related data, groups of two (or three) bars can be shown. For
double-baror triple-bar graphs,a keyis used to explain the meaning of each type of
bar in a group.596 Chapter 7 Graphs and Statistics
EXAMPLE (^2) Speed of Animals The following bar graph shows the
maximum speeds for several animals over a given distance.
a.What animal in the graph has the fastest maximum speed?
b.What animal in the graph has the slowest maximum speed?
c.How much greater is the maximum speed of a lion compared to that of a
coyote?
StrategyWe will locate the name of each desired animal on the vertical axis and
move right to the end of its corresponding bar.
WHYThen we can extend downward and read the animal’s maximum speed on
the horizontal axis scale.
Solution
a.The longest bar in the graph has a length of 70 units and corresponds to a
cheetah. Of all the animals listed in the graph, the cheetah has the fastest
maximum speed at 70 mph.
b.The shortest bar in the graph has a length of approximately 9 units and
corresponds to a chicken. Of all the animals listed in the graph, the chicken
has the slowest maximum speed at 9 mph.
c.The length of the bar that represents a lion’s maximum speed is 50 units long
and the length of the bar that represents a coyote’s maximum speed appears
to be 43 units long. To find how much greater is the maximum speed of a lion
compared to that of a coyote, we subtract
50 mph – 43 mph = 7 mph
The maximum speed of a lion is about 7 mph faster than the maximum speed
of a coyote.
Subtract the coyote’s maximum speed
from the lion’s maximum speed.
Zebra
Reindeer
Lion
Giraffe
Elephant
Coyote
Chicken
Cheetah
Cat (domestic)
02030405010
Miles per hour
Source: Infoplease.com
60 70 80
Maximum Speed of Animals
Self Check 2
SPEED OF ANIMALSRefer to the
bar graph of Example 2.
a.What is the maximum
speed of a giraffe?
b.How much greater is the
maximum speed of a coyote
compared to that of a
reindeer?
c.Which animals listed in the
graph have a maximum speed
that is slower than that of a
domestic cat?
Now TryProblem 21
EXAMPLE (^3) The U.S. Economy The following bar graph shows the
total income generated by three sectors of the U.S. economy in each of three years.
a.What income was generated by retail sales in 2000?
b.Which sector of the economy consistently generated the most income?
c.By what amount did the income from the wholesale sector increase from 1990
to 2007?
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