1. Chapter 3 Measures Of Central Tendency
The Mode
The Median
Other Measures of Position: Percentiles, Deciles and Quartiles
The Mean
Some Characteristics of the Mean
Choosing a Measure of Central Tendency

2. Measures of Central Tendency
Mode - most common score
Median - middle score
Mean - average score

3. Use the Mode Variables are measured at a nominal level.
You want a quick and easy measure of ordinal and interval-ratio variables.
You want to report the most common score.

4. Use the Median Variables are measured at the ordinal level.
Variables measured at the interval-ratio level have highly skewed distributions.
You want to report the central score.
The median always lies at the exact center of a distribution.

5. Use the Mean Variables are measured at the interval-ratio level.
You want to report the typical score.
You anticipate additional statistical analysis.

6. Characteristics of the Mean
It is the point in a distribution of scores around which all other scores cancel out.
The mean is the point of minimized variation.
The mean is affected by every score in the distribution and is pulled in the direction of extreme scores.