Construction of a bar graph :
Steps :

1.     On the graph paper draw a horizontal line (x-axis) and a vertical line (y-axis)
2.     Along the horizontal line, mark points at equal distances and write the names of the items for which the data is to be represented.
3.     Choose a suitable scale which shall determine the height of the bars.
4.     Locate the heights of different bars according to scale.
5.     On x-axis draw bars of equal width according to the required height.
6.     Keep the distance between the bars the same.

Drawing a bar graph : Let us draw a bar graph for this data. First of all draw a horizontal line and a vertical line. On the horizontal line we will draw bars representing each fruit and on vertical line we will write numerals representing number of students.
Let us choose a scale. It means we first decide how many students will be represented by unit length of a bar.
Here, we take 1 unit length to represent 1 student only. We get a bar graph as shown in adjoining figure. Ex. 4 : Read the bar graph given below and answer the following questions. (i)    What is the total number of students in all the clubs together ?
Sol.     20 + 30 +40 + 20 = 110 students

(ii)    Which club has more students and how many ?
Sol.     Drama club, 40 students

(iii)    Which club have equal number of students ?
Sol.     Cricket club and music club

(iv)     How any students are there in hockey club ?
Sol.     30 students.

(v)    What information is given in the bar graph ?
Sol.     The bar graph represetns the number of members of different sports clubs.