A bar graph is a pictorial representation of numerical data in the form of rectangles or bars of equal width and varying heights. To represent data on a bar graph we select a suitable scale and this scale determines the heights of the rectangles.
Students of class 7B were given certain data of marks for two terms and asked to compare the marks obtained in all the subjects by a student in the first and second term examinations through a double bar graph. Materials required for this activity were graph paper, strips of paper in two different colours of width 1cm, a pair of scissors and glue.
This activity helped the students to prepare bar graphs for numerical data of various types, including frequency data making them more confident and giving them practical experience for conceptual retention.