Tuesday, February 06, 2007
Bell Curves
(This is not really a new post. I have taken the Bell Curve exerpt from my previous post so I can link to it, and only it. I’ve modified it so that it can stand alone.)
Bell curves are used because the picture they present allows us to figure out where the normal range is, because you can see it.
“Normal” is typically drawn as the mid point in the decline, on either side of the curve (as the example above illustrates).
Bell curves can be higher or flatter, depending on the data.
The slopes on each side don’t have to match. One slope can be more gradual while the other side severe.
In any event, they tell us something. What they tell us depends on what the underlying data is. Some general rules:
1. The majority will be represented in the middle (or the data was inconclusive or the study faulty).
2. To the right (shown in the gradations of pink) the occurrence/tendencies are greater.
3. To the left (shown in gradations of blue) the occurrence/tendencies are fewer.
When folks bring up anecdotes that don’t fit the general rule (or the “norm"), they are just that, not in the norm.
“Normal” isn’t a value judgment and is not an insult. It is an observable fact on a bell curve. If facts are offensive or insulting, get over it.
Something (or a something about a person) that is not in the normal range doesn’t mean the normal range doesn’t exist, only that the thing (or thing about a person) they’re describing is to the right or left of normal.
Being right or left of the normal range (or in the normal) range is not good or bad. Higher intelligence, for example, is to the right of the normal range. It would be correct to say, very high IQ is abnormal. If you are thinking that every bell curve presents data that is to the right, good, and to the left, bad, do not do that. The data (and your own opinion on the value of the item) determines bad or good.
- Preaching to the Choir (11/30/2008)
- Happy Thanksgiving (11/27/2008)
- Cooking (11/26/2008)
- Ammo Day (11/19/2008)
- Satire (11/17/2008)
Posted 02/06/2007 12:07 PM CDT • Print Vers.
