# Formula for Central Tendency

MEAN.

You probably already know this formula. A mean is the average of scores. We like to use it becuase we don’t have to arrange the scores in any particular order before calculating it. We just add up all the numbers and divide by the number of scores. In statistical vocab we “sum” the numbers and divided the sum by N (the number of scores).

∑X/N

MEDIAN

A median requires that we put the numbers in order (from high to low, or low to high). The median is the score in the middle (if there are an odd number of scores) or the average of the two middle-most scores (if there are an even number of scores). That too much work, so we prefer the mean.

There is no easy formula for median.

MODE

The mode is the most popular score (most common). If you plot a distribution, the mode will be the highest spot on the distribution. It will be the top of the mountain. If your mountain has more than one peak, the distribution will be bimodal (2 high spots) or multimodal (several high spots).

There is no easy formula for mode.

NOW YOU CHOOSE:

Day 2: Central Tendency

A Bit More About Central Tendency

Even More About Central Tendency

More Examples

More Mean Examples

More Median Examples

Median Is Middle Of Distribution

More Mode Examples

Impact of Outlying Scores

On The Mean

On The Median

On The Mode

How To Calculate Central Tendency

Calculating The Mean

Calculating The Median

When There’s No Middle-Most Score

Calculating The Mode

Formulas For Central Tendency

Basic Facts About Central Tendency

Vocabulary

Quiz 2

Summary

## Comments

Feel free to leave a comment...and oh, if you want a pic to show with your comment, go get a gravatar!