Tables nand Graphs in
Non-Mathematics Courses

If you flip through texts books for courses such as chemisty, political science, psychology, and economics, you will see a variety of tables, graphs and charts. Since there is so much information presented in these kinds of visual displays, it is important to have a foundation in extracting information from them. Below are two examples that demonstrate the kinds of displays found in introductory economics textbooks.

Example

The Profitability of Investment Depends on the Interest Rate
(1) (2) (3) (4) (5) (6) (7)
Project Total Investment
in Project		 Annual Revenues per $1000 Invested Cost per $1000 of Project at Annual Interest Rate of: Annual Net Profit per $1000 Invested at Annual Interest Rate of:
($ in millions) ($) 10% ($) 5% ($) 10% ($)
(6) = (3) - (4)		 5% ($)
(7) = (3) - (5)
A 1 1,500 100 50 1,400 1,450
B 4 220 100 50 120 170
C 10 160 100 50 60 110
D 10 130 100 50 30 80
E 5 110 100 50 10 60
F 15 90 100 50 -10 40
G 10 60 100 50 -40 10
H 20 40 100 50 -60 -10

  • The economy has eight investment projects, ranked in order of return. Column (2) shows the investment in each project. Column (3) calculates the perpetual return each year per $1000 invested. Columns (4) and (5) then show the cost of the project, assuming all funds are borrowed, at interest rates of 10 and 5 percent; this is shown per $1000 of the project.
  • The last two columns calculate the annual net profit per $1000 invested in the project. If net profit is positive, then profit-maximizing firms will undertake the investment; if negative, the investment project will be rejected.
  • Note the cutoff between profitable and unprofitable investments moves as the interest rate rises. (Where would the cutoff be if the interest rate rose to 15 percent per year?)

From: Samuelson P. A. & Nordhaus, W. D. (1995) Macroeconomics (p. 112). New York: McGraw-Hill.

Tables are one commonly used means of visually displaying data. The table in the example above is very complex. Imagine trying to explain this in paragraph form. The table helps to make it easy to locate individual pieces of information from the data.

Example

Figure 5-2: The distribution of income
among families, 1993

Personal income is quite unequally distributed in the United Stats. An equal distribution would mean that all vertical bars would pe equal to the horizontal line drawn at 20 percent. In fact, the richest fifth of the families gets over eleven times as much income as does the poorest fifth.

From: McConnell & Brue (1996)
Mactoeconomics (p 75). New York: McGraw-Hill.

This second example illustrates one of the common types of graphs used in textbooks, a bar graph. This, along with tables and circle graphs, are commonly used visual displays.

In many of your courses, you will come across many tables and graphs so it is important for you to be able to both read and construct them. You will be asked to analyze the information presented. You may also be asked to construct these kinds of visual displays of information. This book provides you with the skills you will need to (1) analyze visual displays using tables, circle graphs, and bar graphs, and (2) construct each of these.

The skills you will learn in this book are to:

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