For Use in
Principles of Economics I (Macroeconomics) &
Principles of Economics II (Microeconomics)

Making and Using Graphs

(1 of 2)

Overview

1.  Review

bulletWhat questions do you have:
bulleton hardware, software,
bulletregistration, how to order text & study guide,
bulletthe syllabus, 
bullethow to contact
bulletyour instructor Mr. Tom Meyer,
bulletPatrick Henry Community College (PHCC),
bulletPHCC technical support?
bulletDo you have questions about:
bullethow to determine the weekly reading assignment,
bulletwhat the course objectives are,
bulletthe number, date, or weight of the exams,
bulletinstructor policies regarding attendance?
bulletIf taking the class in my immediate presence:
bulletwill you cooperate by signing in before class;
bulletmaking and displaying a name tag;
bulletobtaining and consulting a study partner:
bulletwhen absent or tardy
bulletto compare notes
bulletto help each other between classes and before exams;
bulletparticipating in review sessions before exams?

 

2.  Get Acquainted with your  Economics in Action (EIA 3.0) cd-rom tutorials

Here are the steps you take to install and run your tutorial.

bulletStep 1:
bulletStart your computer and close any open Windows programs.
bulletInsert your EIA 3.0 CD-rom in your computer.  Before you can start Economics in Action  with a 1-2-3 everyday sequence of mouse clicks on --
bullet(1) Start -
bullet(2) Programs -
bullet(3)Click EIA 3.0 icon -- you have to install the EIA 3.0 program.  The installation process creates the icon.  So do the installation process in Step 2 next. 

 

bulletStep 2: To install EIA 3.0
bulletClick you mouse on My Computer;
bulletLocate and click on your cd-rom drive containing your EIA 3.0 cd-rom;
bulletLocate and click on the blue-screened-computer icon labeled setup.exe. 
bulletReboot your computer.
bulletRunning setup.exe should create a red EIA 3.0 icon accessible from your desktop so that from now on you can skip step 2.
bulletStep 3:  From now on
Starting and running EIA 3.0 is as simple as
bulletStart your computer.
bulletInsert your EIA 3.0 CD-rom in your computer. 
bulletPerform the start Economics in Action  with a 1-2-3 everyday sequence of mouse clicks on
bullet(1) Start -
bullet(2) Programs -
bullet(3)Click EIA 3.0 icon


How to use the main screen in EIA 3.0

The main screen in EIA 3.0 offers you a menu of five choices.  Take the tutorial on how to use EIA 3.0 called Using EIA first.  To take Using EIA, select it with your mouse and click.  You can guide yourself through the EIA sequence of slides by clicking on forward and back near the upper right-hand corners of the slides.

You'll use other portions of your Economics in Action CD beginning with week #2 in which we study the chapter called Markets in Action. 

If you're having technical difficulties
If you have trouble with these steps contact Mr. Mark Nelson, the course technical assistant in the PHCC Library Learning Center by calling:

Mark Nelson
(540) 656-0275

3.  Course Objectives

List the first two course objectives from your text page 19:


1.


2.


  

4.  Outline

bullet

I. Graphing Data

A. Graphs are valuable tools that clarify what otherwise might be obscure relationships.

B. Graphs represent "quantity" as a distance.

C. Two-variable graphs use two perpendicular scale lines.

1. The vertical line is the y-axis.

2. The horizontal line is the x-axis.

3. The zero point in common to both axes is the origin.

D. Three types of graphs are scatter diagrams, time-series graphs, and cross-section graphs.

1. A scatter diagram plots the value of one variable that is associated with the value of another variable. For instance, as illustrated in the textbook, a scatter diagram might show how the average level of consumption is associated with the average income in the United States between 1986 and 1996.

a) Scatter diagrams can make clear the relationship between two variables. For example, they may show that an increase in one variable (say, average income) is correlated with an increase in other variable (say, average consumption). Correlation does not necessarily imply causation.

b) Graphs can have breaks in their axes, indicating that there are jumps in the variable being measured.

c) Graphs may mislead by stretching or squeezing an axis to either over-emphasize or minimize fluctuations in a variable.

2. Time-series graphs plot time along the horizontal axis and the variable being studied along the vertical axis.

a) A time-series graph shows the level of the variable, how it changes over time, whether changes are rapid or slow, and whether there is any trend.

b) Comparing two time-series on a single diagram may require the use of different scales for the variables.

3. A cross-section graph shows the values of an economic variable for different groups at the same point in time. An example, given in the text, of a cross-section graph is the average income in the nation’s ten largest metropolitan areas in 1993.

bullet

II. Graphs Used in Economic Models

A. Graphs are often used to show the relationship between variables in an economic model, a simplified description of the economy or a part of the economy.

B. Graphs often have a basic pattern that can immediately convey the relationship between the variables.

1. A positive relationship (or direct relationship) occurs when an increase (decrease) in the variable on the horizontal axis is associated with an increase (decrease) in the variable on the vertical axis.

a) A relationship illustrated by a straight line is a linear relationship.

2. A negative relationship (or inverse relationship) is shown when an increase (decrease) in the variable on the horizontal axis is related to a decrease (increase) in the variable on the vertical axis.

3. A relationship may have a maximum or a minimum. In this case, a particular value of one of the variables is associated with the highest (or lowest) value for the other variable.

4. If there is no relationship between the variables, so that no matter what happens to one variable the other remains constant, the diagram is either a horizontal or a vertical line.

5. PowerPoint Viewgraphs  (Slides 1 - 21)

(The viewgraphs provide assistance in mastering the course objectives.Take your own notes.)

6.  Optional Web Visits to Sites Relating to Scarcity

Divide into teams of three persons.  Prepare a five minute oral report wherein each of you provides either an introduction, body, or a conclusion from your team's visit to one of the following:


http://www.nuff.ox.ac.uk/Economics/Growth/
Site includes links to statistical datasets, reading, research and matters related to economic growth


http://www.igc/org/thp/
The Ending World Hunger Project links to conference reports, maps, and speeches


http://www.interaction.org/
100 non-profit organizations wanting to help the world's poor with a mission statement, search engine, calendar of events, etc.


http://www.worldbank.org/
The World Bank - a source of financing for less developed countries.


Notes

Introduction




Body

1.



2.



3.



4.



Conclusion

 

7. Let's begin the Questions and Problems (Study Guide pages 13-18)

Most students will find it worthwhile to compare their answers to those of a study partner or the class as a whole.

Complete the study guide True/False, Multiple Choice, and Problems that teach you about:

bullet

Graphing Data;

bullet

Graphs Used in Economic Models.

8. A Half Dozen More Discussion Questions

1.  Suppose you have 150 pairs of variables.  Is it easier to find positive and negative relationships using a graph, or by comparing sets of the variables?
2.  How would a scatter diagram reveal whether two variables are positively or negatively related?
3.  You think that the price of gold rises when inflation rises, and the price of gold falls when inflation falls.  Which diagram or diagrams help you check your hypothesis?
4.  What is the connection between the slope of a line and whether the relationship is direct or inverse?
5.  If a line slopes downward and to the right, is its slope positive or negative?   If a line slopes upward and to the right, is its slope positive or negative?
6.  If a curve has a maximum point, what is the slope of the curve to the left of the maximum point, at the maximum point, and to the right of the maximum point?

9. Homework

1.  Review Key Concepts pages 11 - 12 in your study guide.
2.  Complete the odd-numbered Questions from your study guide pages 13 - 18 and check your answers on pages 19 - 23.
3.  Compare your class notes and your understanding of the homework Questions with your study partner.
4.  Become comfortable with using your Economics in Action tutorial portion called Using EIA.

10. Summary

1.  Graphs sometimes reveal results that are otherwise not observed.
2.  The delta, or "change in" symbol (a triangle) is a shorthand way of helping you find the
slope of a line =
delta Y / delta X
.
3.  If in the future you become puzzled about the math in the book, use this chapter as a reference.
4.   A
scatter diagram plots the values of one variable associated with another variable (such as consumer spending and consumer income for the decade of the1990s.   Scatter diagrams show relationships, such as whether spending rises as income rises.
5.  A
time-series graph plots time on the horizontal axis and the variable being studied on the vertical axis (such as the Dow Jones Industrial Average during the most recent month.  Time-series show how a variable changes over time.
6.  A
cross-section graph shows values of an economic variable for different groups for a point in time (such as average income in major U.S. cities during 1998).

file: Week 01, Part 1

 

Notes

Love for Econ springs eternal!

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Overview