This document is based on a presentation before the Department of Economics faculty at Southern Illinois University Carbondale in fall, 2004. The purpose is to show *some* of what Microsoft Excel can offer as a programming environment for the creation of interactive teaching and learning tools.

- Acknowledgments
- Why Excel?
- The interactivity
- The available "interactive" Excel files
- Primarily for Undergraduates in an Experiments-based Course
- Primarily for More Advanced Microeconomics and Quantitative Work

Several people have helped me master some of the power of Excel.

**John Miller**(Carnegie Mellon University) must head the list. John introduced me to some of the power and richness of Excel as a programming environment. He generously shared his programmed answer keys for the homework assignments in*Experiments with Economic Principles*, a principles textbook coauthored with Ted Bergstrom.**Byron Brown**(Michigan State University) has Excel files where I first saw "spin buttons," the key tool that generates "motion" in Excel charts.

Two others generously helped me solve particular programming problems:

- is a Microsoft Office Excel "Most Valuable Professional", who has been incredibly generous and patient in helping me solve some particularly thorny issues, especially with Excel charts. Thanks, Jon!
**Mickey Soltys**(Southern Illinois University Carbondale)

Why use Excel for interactivity and "almost animation"? After all, there are other tools that are more commonly used. (Macromedia's Flash comes immediately to mind.) The reasons are perhaps few, but they are compelling for me.

My campus is a Microsoft campus, so Excel is available to the students in every lab on campus.

If these objects ran in a browser plug-in, there are at least two considerations. First, the user may not have the plug-in. Admittedly, if Excel is the campus computer labs, then standard plug-ins probably are, too. If the objects ran in a standard plug-in, then use of the modules might be seamless and transparent. While this might be a good thing, I would rather use the modules as some leverage to get the students to use a spreadsheet before they are out of school.

I know Excel; I do not know Flash. I have Excel; I do not have the capability to produce Flash objects.

Actually, "I know Excel" is a bit misleading. What I knew about Excel's capabilities when I began producing these modules was very rudimentary, particularly in comparison to what I have had to learn to achieve certain goals and effects. But I did not have to begin "from scratch."

As Jon Peltier has advised, we should recognize that Excel really isn't particularly secure. By

- hiding a worksheet that has calculations
- "protecting" the controls
- "protecting" the workbook and
- "protecting" the worksheet(s) the students see,

we are merely making it inconvenient for casual hackers to break in.

The source of the so-called "interactivity": we allow the student-user to choose the values of various parameters. Each time the student varies the value of a variable or parameter, the student creates a different numerical problem or example. This means that the students have access to a virtually unlimited number of examples and practice problems. An additional value accrues more to the instructor. When students ask, "What's the answer to Number 4 on the midterm?" (for example), the appropriate interactive Excel file is then a medium or environment in which students can work out the answers for themselves on their own!

The nature and usefulness of the interactive resource relies on several characteristics of a Microsoft Excel file. These characteristics include:

- the multiple-worksheet structure of Microsoft Excel files
- the ability to "hide" a worksheet where calculations and evaluations are done
- the ability to "lock," or "protect," workbook elements such as cells, charts or even entire worksheets.

With access to a virtually limitless number of different examples and practice problems, the students have the flexibility to experiment with the "what if?" questions that can develop their intuition for the basic problem. Finally, once downloaded, the student need not be online to use the resource. There are no "server-side" elements and only Microsoft Excel is required to use the resource.

Below are links for the "interactive Excel files." There are two distinct sets of files: files for students taking Economics 113, a Core Curriculum course with no prerequisites and files for students in intermediate microeconomic theory and beyond.

If you are not familiar with economics experiments, then the supply and demand curves may be unsettling in the beginning. The power of in-class experiments as an instructional pedagogy is in making economics understandable from the personal, or individual level. Each supplier has a reservation price; each demander has a reservation price. Rather than make them all different, there are usually 1–6 reservation prices for demanders and 1–6 reservation prices for suppliers in each experiment. This causes the corresponding demand and supply curves to be "bumpy" in most cases. In any event, the supply curves are not smooth-and-upward-sloping and the demand curves are anything but smooth-and-downward-sloping. That said, browse the linked Excel files below at your leisure.

- Simple demand: all demanders have the same reservation price (28Kb)
- Simple supply: all suppliers have the same reservation price (29Kb)
- Simple market: the corresponding market when all demanders have one reservation price and all suppliers have one reservation price (41Kb)
- Slightly more complicated market: there are two reservation prices on each side of the market (101Kb)
- Profits: practice calculating profits from the graph (92Kb)

- Unit tax (287Kb)

- "Shrinkage" (55Kb)

- Hiring I (48Kb)
- Hiring II (64Kb)
- Labor demand (22Kb)
- Practice minimum wage problems (97Kb)

- Bargain against Professor Mitchell (142Kb)
- Backward induction (56Kb)

- Long-run average cost (187Kb)

- Linear supply; linear demand (36Kb)
- Linear supply; hyperbolic demand (38Kb)
- Linear supply; variable elasticity demand (42Kb)
- Parabolic supply; variable elasticity demand (50Kb)
- Parabolic supply; variable elasticity demand II (no units or numbers on the axes; 49Kb)

- Quasi-linear preferences (224Kb)
- Separately see the income-consumption and price-consumption curves under Cobb-Douglas preferences (298Kb)
- See the income-consumption and price-consumption curves under Cobb-Douglas preferences in one graph (208Kb)

- Cobb-Douglas technology
- Homogeneity: The "spacing" of isoquants depends on the degree of homogeneity of the [symmetric] Cobb-Douglas production function (155.5Kb)
- "Bias": The "orientation" of isoquants depends on the relative values of the exponents for the two-input Cobb-Douglas production function (158Kb)

- Constant elasticity of substitution (CES) (334Kb)
- "Fixed-proportions" technologies (55Kb)

See how the contract curve changes when the parameters of the utility functions change or when the total endowment changes.

- Cobb-Douglas/Cobb-Douglas (415Kb; last revised 3/16/05)
- perfect complements/Cobb-Douglas (273Kb; last revised 3/16/05)
- perfect complements/perfect complements (80Kb; last revised 3/16/05)
- perfect complements/perfect substitutes (61Kb; last revised 3/16/05)
- quasi-linear/Cobb-Douglas (332Kb; added 3/15/05; last revised 3/16/05)
- quasi-linear/perfect complements (283Kb; last revised 3/16/05)
- quasi-linear/quasi-linear (527Kb; last revised 3/16/05)
- quasi-linear/perfect substitutes (283Kb; last revised 3/2/05)
- perfect substitutes/Cobb-Douglas (270Kb; last revised 3/16/05)
- perfect substitutes/perfect substitutes (52Kb; last revised 3/16/05)

Walrasian equilibrium under Cobb-Douglas preferences: Each trader has Cobb-Douglas preferences. The changeable parameters are (1) the exponents in the utility functions, (2) the total endowment available and (3) the initial allocation of the endowment. (The file size is 472Kb.)

- Nash equilibria in a simple game with pure strategies and a 2-by-2 payoff matrix (107Kb)
- Nash equilibria in a simple game with mixed strategies and a 2-by-2 payoff matrix:
*near completion*

- Discrete probability distributions
- Binomial distribution (75Kb)
- Geometric distribution (51Kb)
- Poisson distribution (47Kb)

- Continuous probability distributions
- Uniform distribution (119Kb)
- Normal distribution (336Kb)
- Student's-
*t*distribution (the probability density function for a student's-t random variable is superimposed on the pdf for a standard normal random variable; 312Kb) - Weibull distribution (227Kb)
- Gamma distribution (341Kb)
- Chi-squared distribution (282Kb; the chi-squared distribution with
*n*degrees of freedom is a gamma distribution with alpha =*n*/2 and beta = 2) - Exponential distribution (243Kb; the exponential distribution is a gamma distribution with alpha = 1)

- Chi-squared distribution (282Kb; the chi-squared distribution with
- Beta distribution (195Kb)
- F distribution (307Kb)
- "Extreme-value" distribution (243Kb)

- Statistics
- Confidence intervals:
*near completion* - OLS estimators (with random number generator):
*in development*

- Confidence intervals:

- Present value calculator (1.18Mb)
- Practicing with present value (94.5Kb)

- Matrix inverse (31Kb)
- Conic sections and "eccentricity" (135Kb)
- Eigenvalues I: Specify a 2-by-2 matrix and check its eigenvalues (52Kb)
- Eigenvalues II: Specify a 3-by-3 matrix and check its eigenvalues (54Kb)

- Trajectory of a projectile (75Kb)

[ Professor Mitchell | Economics | 05.28.09 ]