RD Sharma 2020 solution class 9 chapter 24 Measures of Central Tendency Exercise 24.4

Exercise 24.4

Page-24.19

Question 1:

Find out the mode of the following marks obtained by 15 students in a class:

Marks: 4, 6, 5, 7, 9, 8, 10, 4, 7, 6, 5, 9, 8, 7, 7.

Answer 1:

Given that the marks obtained by 15 students are 4, 6, 5, 7, 9, 8, 10, 4, 7, 6, 5, 9, 8, 7 and 7.

Make the following frequency table.

Since the value 7 occurs maximum number of times, that is, 4. Hence, the mode value is 7.

Question 2:

Find the mode from the following data:

125, 175, 225, 125, 225, 175, 325, 125, 375, 225, 125

Answer 2:

The given data is 125, 175, 225, 125, 225, 175, 325, 125, 375, 225, and 125.

Make the following frequency table.

Since the value 125 occurs maximum number of times, that is, 4. Hence, the mode value is

Question 3:

Find the mode for the following series:

7.5, 7.3, 7.2, 7.2, 7.4, 7.7, 7.7, 7.5, 7.3, 7.2, 7.6, 7.2

Answer 3:

The given series is 7.5, 7.3, 7.2, 7.2, 7.4, 7.7, 7.7, 7.5, 7.3, 7.2, 7.6 and 7.2.

Make the following frequency table.

Since the value 7.2 occurs maximum number of times, that is, 4. Hence, the modal value is.

Question 4:

Find the mode of the following data in each case:

(i) 14, 25, 14, 28, 18, 17, 18, 14, 23, 22, 14, 18

(ii) 7, 9, 12, 13, 7, 12, 15, 7, 12, 7, 25, 18, 7

Answer 4:

(i) The given data is 14, 25, 14, 28, 18, 17, 18, 14, 23, 22, 14 and 18.

Make the following frequency table.

Here occurs maximum number of times (that is 4). Hence, the modal value is 14.

(ii) The given data is 7, 9, 12, 13, 7, 12, 15, 7, 12, 7, 25, 18 and 7.

Make the following frequency table.

Since the value 7 occurs maximum number of times, that is, 5. Hence, the modal value is 7.

Question 5:

The demand of different shirt sizes, as obtained by a survey, is given below:
 

Size:	38	39	40	41	42	43	44	Total
Number of persons (wearing it):	26	39	20	15	13	7	5	125

Find the modal shirt sizes, as observed from the survey.

Answer 5:

The demand of different shirt sizes is given as

Here x denotes the size of the shirts and f denotes the number of peoples (frequency) wearing it.

The value 39 occur maximum number of times, that is, 39. Hence, the modal shirt size is 39.