Even today, writing formulas can be a pain

Within the last year and a half, I was asked a question about grades, standards and the normal curve.  I hadn't thought about the subject for quite a long time but the question reminded me that there are still certain mysteries floating around that can affect people's opinions and judgments.

You have seen pictures of the curve, sometimes called the bell curve (some bell!) or Gaussian curve. It looks like this:

People don't always realize that the curve comes from a mathematical formula.  You may remember the formula for the area of a circle: "pi times r squared". It can be surprisingly difficult even in this day of digital everything to write that formula in symbols.  It is much easier to pick up a piece of chalk and write it on a blackboard, if you can still find one.  If you can't, you can do it on a white board with a marker or even on a smart board.  When teaching, access to Google and other search engines, to all the pictures and up-to-date information available on the internet is a tremendous aid.  Smart boards can bring in images and text onto themselves from the internet and show images and drawings and text that the teacher created on the spot in front of the class or earlier and stored in a file.

So, there is a formula for the normal curve and it only has one variable.  For the area of the circle, the only variable is the radius of the circle.  For the "standard" normal curve, the only variable is the z score, the distance above or below the mean.  For those who hate or fear formulas, don't look at what is below.

You can get an idea of how the curve occurs by looking at a picture of a Galton board.

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Bill
Main blog: Fear, Fun and Filoz
Main web site: Kirbyvariety