© 2001 McGraw-Hill Companies

**647**

**8.4** **OBJECTIVES**

**1.** Use a table to create a bar graph

**2.** Read a pie chart

**3.** Use a table to create a pie chart

As we have seen, it is frequently easier to read information from a graph than it is from a table. In this section, we will look at two types of graphs that can be created from tables. We have already learned to read a bar graph. In our first example, we will create one.

**Example 1**

**Creating a Bar Graph**

The following table represents the 1995 population of the six most populated urban areas in the world. Each population is the population of the city plus the population of all of its suburbs. Create a bar graph from the information in the table.

We will let the vertical axis, the vertical line to the left of the graph, represent population. The six urban areas will be placed along the horizontal axis. To create a graph, we must de-cide on the scale for the vertical axis. The following steps will accomplish that.

**1.** Pick a number that is slightly
larger than the biggest
number we are to graph.
30,000,000 is slightly larger
than 27,500,000.

**2.** Decide how long the axis
will be. It is best if this
length easily divides into the
number of step 1. To
accomplish this division, we
will choose 3 inches.
**3.** Scale the axis by dividing it

with hashmarks. Label each hashmark with the

appropriate number. In this graph, each inch will represent 10,000,000 people (the 30,000,000 divided by the 3 inches results in 10,000,000 people/inch).

**Population of the World’s Largest Urban Areas**
**(U.N. Dept. for Economic and Social Info.)**

**City** **1995 Population**

Tokyo, Japan 27,500,000

Mexico City, Mexico 17,500,000

Sao Paulo, Brazil 16,500,000

New York City, USA 16,000,000

Bombay, India 15,000,000 Shanghai, China 14,000,000 30,000,000 20,000,000 1995 Population 10,000,000 [City]

© 2001 McGraw-Hill Companies

Now, the height of each bar is determined by using the scale created for the axis.
Remem-bering that we have 10,000,000 people/inch, we divide each population by 10,000,000. The
result is the height of each bar. The height for Mexico City is 1.75 inches. That would be
inches. Remember, all we can get from a bar graph is a rough approximation of the
actual number.
30,000,000
20,000,000
1995 Population
10,000,000
City
T
okyo
Shanghai
Bombay
New Y
o
rk
City
Sao Paulo
Mexico City
13
4
**C H E C K Y O U R S E L F 1**

*The following table represents the *1995*population of the six most populated cities*
*in the United States. Each population is the population within the city limits, which*
*is why the New York population is so different from the previous table. Create a bar*
*graph from the information in the table.*

**Population of the Largest Cities in the United States**
**(Bureau of the Census, U.S. Dept. of Commerce)**

**City** **1995 Population**
New York, NY 7,500,000
Los Angeles, CA 3,500,000
Chicago, IL 2,750,000
Houston, TX 2,750,000
Philadelphia, PA 1,500,000
San Diego, CA 1,250,000

© 2001 McGraw-Hill Companies

**Example 2**

**Reading a Pie Chart**

This pie chart represents the results of a survey that asked students how they get to school most often.

**(a)** What percentage of the students walk to school?
We see that 15% walk to school.

**(b)** What percentage of the students do not arrive by car?

Because 55% arrive by car, there are 100%55%, or 45%, who do not.
30%
15%
55%
bus
walk
car
**C H E C K Y O U R S E L F 2**

*This pie chart represents the results of a survey that asked students whether they*
*bought lunch, brought it, or skipped lunch altogether.*

**(a)** What percentage of the students skipped lunch?

**(b)** What percentage of the students did not buy lunch?
35%
skip
lunch
20%
45%
buy
lunch
bring
lunch

If we know what the whole pie represents, we can also find out more about what each wedge represents. Example 2 illustrates this point.

As you might expect, a **pie chart**is a circle. Wedges (or sectors) are drawn in the circle
to show how much of the whole each part makes up.

© 2001 McGraw-Hill Companies

**C H E C K Y O U R S E L F 3**

*This pie chart shows how Rebecca spends an average *24*-h school day.*

**(a)** How many hours does she spend sleeping each day?

**(b)** How many hours does she spend altogether studying and in class?
30%
class
25%
sleeping
30%
studying
10%
travel
5%
meals

If we are creating a pie chart, how do we know how much of the circle to use for each piece? To make this decision requires a scale be used for the circle. A standard scale has been established for all circles. As we saw in Chapter 7, each circle has 360°. That means that of the circle has of 360°, which is 90°.

With a protractor, we can now create our own
pie chart.
1
4
1
4
360
180
270
90
**Example 3**

**Interpreting a Pie Chart**

This pie chart shows how Sarah spent her $12,000 college scholarship.

**(a)** How much did she spend on tuition?
50% of her $12,000 scholarship, or $6000.

**(b)** How much did she spend on clothing and entertainment?

Together, 5% of the money was spent on clothing and entertainment, and 0.0512,000 = 600. Therefore, $600 was spent on clothing and entertainment.

35% room and board 10% books and supplies 50% tuition 1% entertainment 4% clothing

© 2001 McGraw-Hill Companies

**Example 4**

**Creating a Pie Chart**

The following table represents the source of automobiles purchased in the United States in 1997. Create a pie chart that represents the same data.

To find the size of the slice for each country, we take the given percent of 360°. We will cre-ate another table column to represent the degrees needed.

Using a protractor, we start with Japan, and mark a section that is 36°.

Again, using the protractor we mark the 18° section for Germany and the 18° section for the other countries.

Japan, 10% Germ any , 5% All o thers, 5 % Japan, 10%

**Source of Automobiles Purchased in 1997 **

**Country of Origin** **Number** **% of total** **Degrees**

U.S. 6,500,000 80 288

Japan 800,000 10 36

Germany 400,000 5 18

All Others 400,000 5 18

(Source:Amer. Auto. Manuf. Assn.)

**Source of Automobiles Purchased in 1997 **

**Country of Origin** **Number** **% of total**

U.S. 6,500,000 80

Japan 800,000 10

Germany 400,000 5

All Others 400,000 5

© 2001 McGraw-Hill Companies

**C H E C K Y O U R S E L F 4**

*Create a pie chart for the following table, which shows TV ownership for all United*
*States homes.*

**TV Ownership (Nielsen Media Research)**

**Number of TVs** **% of U.S. Homes**

0 2%
1 22%
2 34%
3 or more 42%
**C H E C K Y O U R S E L F A N S W E R S**
**1.** **2. (a)**20%; **(b)**55%
**3. (a)**6 h; **(b)**14.4 h
**4.**
2%
0
22%
1
34%
2
42%
3 or
more
1995 Population
City
1,000,000
2,000,000
3,000,000
4,000,000
5,000,000
6,000,000
7,000,000
8,000,000
San Diego,
CA
Philadelphia,
PA
Houston, TX
Chicago, IL
Los Angeles,
CA
New Y
ork, NY

There is no need to measure the remainder of the pie. What is left is the 288° section for U.S.-made cars. Note that we saved the large section for last. It is much easier to mark the smaller sections and leave the largest for last.

Japan, 10% Germ any , 5% All othe rs, 5% U.S., 80%

**Exercises**

**1.** The following table represents the top six metropolitan areas where immigrants were
admitted to the United States in 1996.

Create a bar graph from this information.

**2.** The following information represents the 1997 population of the six largest counties
in the United States.

Create a bar graph from this information.

The following pie chart shows the budget for a local company. The total budget is $600,000.

Find the amount budgeted in each of the following categories.

**3.** Production **4.** Taxes

**5.** Research **6.** Operating expenses

**7.** Miscellaneous

The following pie chart shows the distribution of a person’s total yearly income of $24,000.

Find the amount budgeted for each category.

**8.** Food **9.** Rent
**10.** Utilities **11.** Transportation
**12.** Clothing **13.** Entertainment
30%
food
10%
other
5%
entertainment
10%
clothing
20%
transportation
5%
utilities
20%
rent
Production
45%
Miscellaneous
10%
Taxes
10%
Operating
Expenses
20%
Research
15%
**City** **Population**
Los Angeles, CA 9,145,219
Cook, IL 5,076,786
Harris, TX 3,158,095
San Diego, CA 2,722,650
Maricopa, AZ 2,696,198
Orange, CA 2,674,091
**Area** **Number**
New York, NY 133,168
Los Angeles, CA 64,285
Miami, FL 41,527
Chicago, IL 39,989
Washington, DC 34,327
Houston, TX 21,387

**8.4**

_{Section Date }

**ANSWERS**

**1.**

**2.**

**3.**

**4.**

**5.**

**6.**

**7.**

**8.**

**9.**

**10.**

**11.**

**12.**

**13.**

**653**© 2001 McGraw-Hill Companies

**14.** The following table represents women on active duty in 1998.

Create a pie chart for the information.

**15.** The following table represents the number of Nobel Prize laureates during the years
1901 to 1993.

Create a pie chart for the information.

**Answers**

**1.**

**3.**$270,000

**5.**$90,000

**7.**$60,000

**9.**$4800

**11.**$4800

**13.**$1200

**15.**U.S. 40.48% U.K. 16.43% Germany 14.05% France 5.71% USSR 2.38% Others 20.95% 30,000 60,000 90,000 120,000 150,000 Number New Y ork, NY Los Angeles, CA Miami, FL Chicago, IL W ashington, DC Houston, TX Area

**Country**

**Number**United States 170 United Kingdom 69 Germany 59 France 24 USSR 10 Others 88

**Service** **Number of Women**

Army 56,800
Navy 45,000
Marines 18,600
Air Force 65,700
Coast Guard 36,000
**14.**
**15.**
**654**
© 2001 McGraw-Hill Companies