SUMMARY OF THE MEASURES OF CENTRAL TENDENCY
The mean is the sum of all observations divided by the number of observations. The mean
considers all of the observations and it is greatly affected by extreme values. The mean can be
computed as shown below.
population mean = u = ΣX
sample mean = X = ΣX
The median is the middle observation in a group of observations after arranging them in
ascending or descending order. If there are an even number of observations, the median is found
by taking the mean of the middle two values. Since the median is not affected by extreme values,
it is the more appropriate measure of central tendency when there are extreme values in the
The mode is the most frequently occurring observation in a group of data. A typical application
of the mode would be to determine the most frequent cause or reason for some event when the
causes cannot be numerically measured.