FRAME 42.

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

N

sample mean = X = ΣX

n

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

data.

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.