January 4, 2017

Measures of central tendency


Mean of a sample
The mean is the arithmetic average of data. It is affected by outliers, which are extreme values of data distribution.

The median is the "mid-most" value of a data distribution. It is the value above which or below which or below which have of the data points lie. The median is the 50th percentile of a distribution.

The mode is the most commonly obtained value or values on a data scale. It is also the highest point of a peak on a frequency distribution.

1. Gaddis G, Gaddis M. Introduction to biostatistics: part 2, descriptive statistics. Ann Emerg Med 1990;19:309-315.