Question

Class mark of a class is obtained by using
(a) upper limit
(b) $\dfrac{1}{2}\left[ \text{upper limit}-\text{lower limit} \right]$
(c) $\dfrac{1}{2}\left[ \text{upper limit + lower limit} \right]$
(d) $\dfrac{1}{2}\left[ \text{upper limit + lower limit} \right]-1$

Answer 1

Hint: We will look at the definition of a class. Then we will define the class interval. The class interval leads us to the concept of the class limits. We will see the definition of the class mark. Then we will see the method to compute the class mark using the upper limit and lower limit of a class.

Complete step by step answer:
A class is defined as a grouping of values for computation of frequency distribution. The class interval is the range of the values in a class. The endpoints of the class interval are called as class limits. The minimum value in a class is its lower limit and the maximum value in a class is the upper limit.
The class mark is defined as the central value of a class. It is also called as the average of the values of the lower limit and upper limit of the given class. From this definition, we can see the method of computing the class mark as follows,
$\text{class mark = }\dfrac{1}{2}\left[ \text{upper limit + lower limit} \right]$

So, the correct answer is “Option C”.

Note: There are many definitions involved to understand the definition of some concepts. It is essential that we are familiar with all the basic definitions. The range of a class can be found by subtracting the value of the lower limit of the class from the value of the upper limit of the class. Once we know the classes, class marks and frequency distribution, we can draw histogram, frequency polygon or frequency curve.