In the latter case, " average " nearly always refers to the arithmetic mean, but more precisely it refers to a " typical value ", or with more jargon, a " measure of central tendency ".
12.
Some measures that are commonly used to describe a data set are measures of central tendency and measures of variability or mode, while measures of variability include the standard deviation ( or variance ), the minimum and maximum values of the variables, kurtosis and skewness.
13.
For interval level variables, the arithmetic mean ( average ) and standard deviation are added to the toolbox and, for ratio level variables, we add the geometric mean and harmonic mean as measures of central tendency and the coefficient of variation as a measure of dispersion.
14.
For " n " = 3, the modified mean is the median, and instead the mean is the most efficient measure of central tendency for values of " ? " 2 from 2.0 to 6.0 as well as from & minus; 0.8 to 2.0.
15.
Note that some of these ( such as median, or mid-range ) are measures of central tendency, and are used as estimators for a location parameter, such as the mean of a normal distribution, while others ( such as range or trimmed range ) are measures of statistical dispersion, and are used as estimators of a scale parameter, such as the standard deviation of a normal distribution.
