Range calculates the difference between two middle observations.

Variance is square root of standard deviation.

MEAN deviation is the average amount of scatter of the items, in a distribution, from either the mean or the median or the mode, ignoring the signs of deviations.

Interquartile range is the difference between the third quartile and the first quartile.

Relative measure of dispersion is presented in the same way in which the unit of distribution is given.

In the field of quality control, range provides an upper and lower limit within which product quality should fall.

Arithmetic mean is based on very few observations of a series and is not capable of further mathematical treatment.

Median of the distribution is the value of variable which divides it into four equal parts.

Quartile deviation is not based on all the observations. In fact, it ignores 50 per cent items of any series.

Median is the positional average of middle, which is why we need to arrange the data before we can perform any calculation.

In a data series, when values of the observations are arranged in ordered sequence, deciles divide the data in one hundred equal parts.

Mode is not based upon all the observations.

Arithmetic mean is generally denoted by x̄ or AM.

If all observations of an individual series are same, then range Quartile deviation and standard deviation will be 1.

The variance of first 13 natural numbers is 13.

The absolute measure of dispersion for range is called the coefficient of range.

Standard deviation, variance, and range are measures of variability.

The median of a set of numbers will always be one of the numbers in the set.

The median of the following set is 13.

9, 12, 11, 13, 15, 11, 10