Question

Explain how to calculate the variability with equations.

Answer 1

Variability:

                    Variability means the spread of values in data set. i.e it is dispersion in data set.

Range:

            It is difference between the largest and smallest values of a set of data. It is simply

Range= largest value – lowest value.

Interquartile Range:

                                    It is equal to the difference between the upper quartile and lower quartiles. Symbolically (Q3-Q1). It tells about the range of the middle 50 percent values of a set of data. In this measure lower 25 percent and upper 25 percent values are excluded.

Variance:

                 The average of the square of the deviations taken from mean is called variance. The population variance is denoted by σ² and its estimate by s².

i.e

σ² =

Standard Deviation:

                                    The positive square root of the variance is called standard deviation. i.e

σ= σ² or s=s²