Page 531 - Basic College Mathematics with Early Integers

508 C HAPTE R 7 I STATISTICS AND PROBABILITY

PRACTICE 2 Example 2 Calculating Lunar and Planetary Explorations
Use the pictograph shown in
Example 2 to answer the The following pictograph shows the approximate number of spaceflights by vari-
following questions: ous countries or space consortia for lunar or planetary explorations from 1957 to
the present day. Use this pictograph to answer the questions. (Source: University
a. Approximate the number of of Michigan Corporation for Atmospheric Research)
spaceflights undertaken by
the European Space Agency.
b. Approximate the total Lunar and Planetary Space Explorations
number of spaceflights
undertaken by the European
USA
Space Agency and Japan.
USSR/Russia
European
Space
Agency
7 Spaceflight trips
Japan

a. Approximate the number of spaceflights undertaken by the United States.
b. Approximate how many more spaceflights have been undertaken by the
USSR/Russia than by the United States.
Solution:

1
a. The United States corresponds to 12 symbols, and each symbol represents
2
7 spaceflights.This means that the United States has undertaken approximately
1
12 # 7 = 87.5 L 88 spaceflights for lunar and planetary exploration.
2
1
b. The USSR/Russia shows 16 symbols, or 3 more than the United States. This
2
1
means that the USSR/Russia has undertaken 3 # 7 = 24.5 L 25 more space-
2
flights than the United States.
Work Practice 2

Objective Reading and Constructing Bar Graphs

Another way to visually present data is with a bar graph. As we have seen in this
text, bar graphs can appear with vertical bars or horizontal bars. Although we have
studied bar graphs in previous sections, we now practice reading the height or
length of the bars contained in a bar graph.An advantage to using bar graphs is that
a scale is usually included for greater accuracy. Care must be taken when reading
bar graphs, as well as other types of graphs—they may be misleading, as shown later
Copyright 2012 Pearson Education, Inc.
in this section.

Answers
2. a. 7 b. 14