Measure of Dispersion part (1)

The measures of dispersion are used examine the spread of the data. These are the methods used:

• Range
• Quartiles
• Variance
• Standard Deviation

RANGE

Range is the simplest method for measuring dispersion. It is the difference between the largest value and the smallest value in the data set. 

R = X_max – X_min

Example:
3, 5, 7, 9, 16, 18, 25

Range, R = 25 – 3

   = 22

QUARTILE

Quartiles divide a set of ordered data into four groups with equal numbers of values.

The interquartile range (IQR) is Q₃ – Q_1.

Example:

Calculate the median and interquartile of Brunei Darussalam’s temperature during the day in the following dates.