Question

Explain the meaning of each of the following terms:
(i) Variate
(ii) Class interval
(iii) Class size
(iv) Class mark
(v) Class limit
(vi) True class limits
(vii) Frequency of a class
(viii) Cumulative frequency of a class

Answer 1

(i) $\text{Variate : Any character which is capable of taking several different values is called a variant or a variable.}$

(ii) $\text{Class interval : Each group into which the raw data is condensed is called class interval.}$

(iii) $\text{Class size: The difference between the true upper limit and the true lower limit of a class is called its class size.}$

(iv) $\text{Class mark of a class: The class mark is given by}$

$=\frac{\text{Upper limit + Lower limit}}{2}$.

(v) $\text{Class limit: Corresponding to a class internal, the class limits}$ $\text{may be defined as the minimum value and the maximum value the class interval may contain.}$

$\text{The minimum value is known as the lower class limit (LCL)}$& $\text{and the maximum value is known as the upper class limit (UCL)}$

(vi) $\text{True class limits: In the exclusive form, the upper and}$ $\text{lower limits of a class are respectively known as true upper limit and true lower limit.}$

$\text{In the inclusive form of frequency distribution, the true lower limit of a class is obtained by subtracting 0.5 from}$ $\text{the lower limit and the true upper limit of the class is obtained by adding 0.5 to the upper limit.}$

(vii) $\text{Frequency of a class: Frequency of a class is the number of times an observation occurs in that class.}$

(viii) $\text{Cumulative frequency of a class: Cummulative frequency of a class is the sum total}$ $\text{of all the frequencies up to and including that class.}$