Numerical Measures of Central Tendency and Variability

Read these sections and complete the questions at the end of each section. First, we will define central tendency and introduce mean, median, and mode. We will then elaborate on median and mean and discusses their strengths and weaknesses in measuring central tendency. Finally, we'll address variability, range, interquartile range, variance, and the standard deviation. 

Central Tendency

Central tendency is a loosely defined concept that has to do with the location of the center of a distribution. The section "What is Central Tendency" presents three definitions of the center of a distribution. "Measures of Central Tendency" presents the three most common measures of the center of the distribution. The three simulations that follow relate the definitions of the center of a distribution to the commonly used measures of central tendency. The findings from these simulations are summarized in the section "Mean and Median". The "Mean and Median" allows you to explore how the relative size of the mean and the median depends on the skew of the distribution.

Less frequently used measures of central tendency can be valuable supplements to the more commonly used measures. Some of these measures are presented in "Additional Measures". Finally, the last section compares and summarizes differences among measures of central tendency.

Source: David M. Lane,
Public Domain Mark This work is in the Public Domain.