Average
This is an old revision of this page, as edited by Dpbsmith (talk | contribs) at 02:36, May 15, 2007. It may differ significantly from current revision.
Average is the sum of a group of numbers divided by the number of values in the group. For example, the average of 3, 5, and 7 is .
Another term for average is the arithmetic mean.
The other two common types of average are the median and the mode.
- The median is the value which splits the group of numbers in the middle: half are higher, half are lower.
- The mode is the most common number.
An "analog computer" for the average
If equal weights are hung from a ruler, and the weight of the ruler itself is small enough to be neglected, the distance marking at which the ruler will balance can be shown to be the average of the distance markings at which the weights are hung.
In this picture, weights are hung at the 1, 9, and 11 inch marks. The average of 1, 9, and 11 is 7. The ruler will balance if it his hung at the 7 inch mark. This can be considered as an example of an "analog computer" for the average.