## NCERT solutions for class 9 Maths

**Statistics**

**Chapter 14**

**Exercise 14.3**

**Ex 14.3 Question 1.**

**A survey conducted by an organisation for the cause of illness and death among the women between the ages 15-44 (in years) worldwide, found the following figures (in %)**

**(i) Represent the information given above graphically.**

**(ii) Which condition is the major cause of women’s ill health and death worldwide?**

**(iii) Try to find out, with the help of your teacher, any two factors which play a major role in the cause in (ii) above being the major cause.**

**Solution:**

(i) Graphical representation

(ii) Reproductive health conditions is the major cause of women’s ill health and death worldwide .

(iii) Two factors responsible.

- Lack of medical facilities.
- Lack of correct knowledge of treatment.

**Ex 14.3 Question 2.**

**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.**

**Solution:**

(i) The bar graph :

(ii) We conclude that number of girls per thousand boys are maximum in scheduled tribe section whereas minimum in urban section.

**Ex 14.3 Question 3.**

**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?**

**Solution:**

(i) The required bar graph is shown below:

(ii) The political party A won the maximum number of seats.

**Ex 14.3 Question 4.**

**The length of 40 leaves of a plant measured correct to one millimetre and the obtained data is represented in the following table**

**(i) Draw a histogram to represent the given data.**

**(ii) Is there any other suitable graphical representation for the same data?**

**(iii) Is it correct to conclude that the maximum number of leaves 153 mm long and Why?**

**Solution:**

(i) The given frequency distribution table is not continuous. Therefore, first we have to modify it to be continuous distribution.

Thus, the modified frequency distribution table is:

Now, the required histogram of the frequency distribution is shown below :

(ii) Yes, other suitable graphical representation of the data is ‘frequency polygon’.

(iii) No, it is not a correct. The maximum number of leaves lie in the class interval 145 – 153.So, it is not necessary that all have their lengths as 153.

**Ex 14.3 Question 5.**

**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 lifetime of more 700 h?**

**Solution:**

(i) The required histogram is shown below:

(ii) Number of lamps having life time of more than 700 hours = 74 + 62 + 48 = 184.

**Ex 14.3 Question 6.**

**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:**

To draw a frequency polygon, we mark the class marks along x-axis. Therefore, the modified table is:

So, the two frequency polygons are as shown below:

From the above frequency polygon, we can see that the performence of students of section ‘A’ is better than the students of section ‘B’ in terms of good marks.

**Ex 14.3 Question 7.**

**The runs scored by two teams A and B on the first 60 balls in a cricket match are given below**

**Represent the data of both the teams on the same graph by frequency polygons.**

**Solution:**

It can be observed that the class intervals of given data are not continuous. Therefore, we first modify the distribution as continuous.

Now, the required frequency polygons are as shown below:

**Ex 14.3 Question 8.**

**A random survey of the number of children of various age groups playing in a park was found as follows:**

**Draw a histogram to represent the data above.**

**Solution:**

Here, it can be observed that the data has class intervals of varying width. The propertion of children per 1 year interval can be calculated as follows:

Now, the required histogram is shown below:

**Ex 14.3 Question 9.**

**100 surnames were randomly picked up from a local telephone directory and a frequency distribution of the number of letters in the English alphabet in the surnames was found as follows**

**(i) Draw a histogram to depict the given information.**

**(ii) Write the class interval in which the maximum number of surnames lie.**

**Solution:**

(i) Since, the given frequency of class intervals of distribution are unequal, and the minimum class size = 6 – 4 = 2.

The required histogram is shown below:

(ii) The class interval in which the maximum number of surnames lies is 6 – 8 as it has 44 surnames in it. i.e. the maximum for this data.