Spreadsheet Design:
What-If

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One of the advantages of using a computer spreadsheet over using a paper one is the ability to play the "What If" game. It is a very easy game to play. Just change a spreadsheet's data to see what the effect would be. (This is safer when using a copy of the original data!)

A What-If sheet is especially useful in complex situations where a change in one value affects several other values. Another situation is when you would like to experiment with the numbers to find out what they need to be for you to achieve a certain goal.

A Sample What If sheet: Grade Calculator

Background Info: You would like to figure out if you can get a A in a course, which requires an average of 90 or greater. Suppose your grade is made up of 50% test average, 25% homework average, and 25% quiz average. Sometimes there are extra assignments which let you can earn extra points that are added to your test grades. Below is an example of a spreadsheet for calculating your grade using these rules.

You will have 2 more tests, 2 more graded homework sets, and 2 more quizzes. Can you raise your grade to 90?? By using the sheet as a What-If sheet, you can plug in various combinations of grades to see if it is possible to get your A.

Click on the illustration to see three sets of additional grades:

a.  All remaining grades = 100
     (Wouldn't that be cool! Not very likely to happen though.)

b.  All remaining grades = 90
     (Not bad but since the current grade is less than 90, it won't average ABOVE 90, will it?)

c. All remaining grades = 90 plus two 10 point bonuses.

The last one rounds up to 90 - an A! But, can you actually do it?? That's always the real question.
 

~~  1 Cor. 10:31 ...whatever you do, do it all for the glory of God. ~~

Last updated: 02 May 2012