Central tendency

A central tendency could be defined as a central value for a probability distribution. The central tendency could be also called the center of a random variable distribution to cluster around its mean, mode, or median.

Mean

The mean usually called ‘average’, is the sum of all the data points over the number of data points. It is calculated using the following formula:

Where:

  • is the mean for a population
  • is the mean for a sample
  • N is the number of items in the data set (population)
  • n is the number of items in the data set (population)
  • is the sum of all the data points

Example

Given the data set [10, 12, 14, 16]. Calculate the mean?

Median

The median of a data set is the value separating the higher half from the lower half, otherwise, when we line up all the data points in the set from least to greatest, it may be thought of as the “middle” value when we look at the number or pair of numbers in the middle.

Example 1

Given the data set [1, 3, 3, 6, 7, 8, 9]. Find the Median.