Question

Look at the following table below.
$\begin{array}{cc}\text{Class interval}& \text{Class mark}\\ 0-5& --\\ 5-10& --\\ 10-15& \\ 15-20& \end{array}$

Fill in the blanks with the class marks of the corresponding class intervals.

• A. 0, 5
• B. 2.5, 7.5
• C. 3, 8
• D. 5, 10

Answer 1

The correct option is B

2.5, 7.5

Class mark for a class interval is given by $=\frac{\text{Upper class limit + Lower class limit}}{2}$
For $1^{st}$ class interval, upper limit is 5 and lower is 0. Thus, class mark will be 2.5.
For $2^{nd}$ class interval, upper limit is 10 and lower limit is 5. Thus, class mark will be 7.5.