The following table gives the distribution of students of two sections according to the marks obtained by them:

Represent the marks of the students of both the sections on the same graph by two frequency polygons. From the two polygons compare the performance of the two sections.

Solution:

Frequency polygons can be drawn independently without drawing histograms. This requires the midpoints of the class intervals used in the data. The mid-points are called class-marks.

Class Mark = (Upper Limit + Lower Limit)/2

Now, the data table with the inclusion of class marks is as follows:

The frequency polygon for the above data can be constructed by:

1. Taking class marks on the x-axis.
2. Taking ‘frequency’ on the y-axis with an appropriate scale of 1 unit = 2 students as the lowest frequency value observed is 1 and the highest frequency value is 19.

It can be observed that the performance of students of Section ‘A’ is better than the students of Section B as section ‘A’ shows more students securing marks between class intervals ‘40 – 50’ and ‘30 – 40’.

☛ Check: NCERT Solutions Class 9 Maths Chapter 14

Video Solution:

The following table gives the distribution of students of two sections according to the marks obtained by them: Represent the marks of the students of both the sections on the same graph by two frequency polygons. From the two polygons compare the performance of the two sections.

NCERT Solutions for Class 9 Maths Chapter 14 Exercise 14.3 Question 6

It is given that distribution of students of two sections according to the marks obtained. The marks of the students of both the sections has been represented on the same graph by two frequency polygons. It can be observed that the performance of students of Section ‘A’ is better than the students of Section B as section ‘A’ shows more students securing marks between class intervals ‘40 – 50’ and ‘30 – 40’ class.

☛ Related Questions:

• The following data on the number of girls (to the nearest ten) per thousand boys in different sections of Indian society is given below. i) Represent the information above by a bar graph. ii) In the classroom discuss what conclusions can be arrived at from the graph.
• Given below are the seats won by different political parties in the polling outcome of a state assembly elections: i) Draw a bar graph to represent the polling results. ii) Which political party won the maximum number of seats?
• The length of 40 leaves of a plant are measured correct to one millimetre, and the obtained data is represented in the following table: i) Draw a histogram to represent the given data. [Hint: First make the class intervals continuous] ii) Is there any other suitable graphical representation for the same data? iii) Is it correct to conclude that the maximum number of leaves are 153 mm long? Why?
• The following table gives the lifetimes of 400 neon lamps: (i) Represent the given information with the help of a histogram. (ii) How many lamps have a life time of more than 700 hours?