Question

Construct a histogram from the following distribution of total marks obtained by 60 students of class VIII.

$\begin{array}{ccc}\text{Class Marks (Mid points)}& \text{Number of students}& \text{Class Interval}\\ 150& 7& \\ 160& 14& \\ 170& 9& \\ 180& 12& \\ 190& 15& \\ 200& 3& \end{array}$

Answer 1

As class marks (mid points) are given, class intervals are to be calculated from the class marks.

Step 1: Find the difference between two successive classes. h = 160 -150 = 10

Step 2: Calculate lower and upper boundaries of every class with class mark $x$, as $x–\frac{h}{2}$ and $x+\frac{h}{2}$.

Step 3: Choose a suitable scale. X-axis 1 small division = 2.5 units and on Y-axis 1 small division = 1 unit.

Step 4: Draw rectangles with class intervals as bases and the corresponding frequencies as the heights.

$\begin{array}{ccc}\text{Class Marks (Mid points)}& \text{Number of students}& \text{Class Interval}\\ 150& 7& 145-155\\ 160& 14& 155-165\\ 170& 9& 165-175\\ 180& 12& 175-185\\ 190& 15& 185-195\\ 200& 3& 195-205\end{array}$