Q. 1. Define the following terms:

1. Range
2. Standard Deviation
3. Variance
4. Mean Deviation

(i) Range
Ans. Range is the difference between the value of the smallest item and the value of the largest item included in the distribution. Range = L - S
Where:
L = Largest item
S = Smallest item
Coefficient of Range = (L - S)/(L + S)

(ii) Standard Deviation
Ans. Standard deviation measures the absolute dispersion or variability of a distribution. It is denoted by s.

(iii) Variance
Ans. Variance is the average squared deviations from the arithmetic mean. It is denoted by s².

(iv) Mean Deviation
Ans. It is the average difference between the items in a distribution from the median or mean of the series. The mean deviation is also known as the average deviation.