NCERT Class 9 Solutions: Statistics (Chapter 14) Exercise 14.4-Part 2 (For CBSE, ICSE, IAS, NET, NRA 2022)

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Mean, Median, Mode, Range and Its Description

Q-4 Find the mode of 14, 25, 14, 28, 18, 17, 18, 14, 23, 22,14, 18.

Solution:

Mode is the number which appears with maximum frequency.

Here, 14 occurs maximum number of times. So, mode is 14.

Q-5 Find the mean salary of 60 workers of a factory from the following table.

Number of Workers and Its Salary
Salary (in ₹)Number of workers
300016
400012
500010
60008
70006
80004
90003
100001
Total60

Solution:

Calculation of Weighted Salary with Number of Workers
Salary (in ₹) ( )Number of workers ()
300016
400012
500010
60008
70006
80004
90003
100001
Total

Mean

Therefore, mean salary of 60 workers is ₹ 5083.33.

Q-6 Give one example of a situation in which

I. The mean is an appropriate measure of central tendency.

II. The mean is not an appropriate measure of central tendency but the median is an appropriate measure of central tendency.

Solution (I) :

Mean is an appropriate measure because it՚s unique value and can be used to compare different groups of data.

Example: Following data represents the weights of the members of a family.

54.9 kg, 62.8 kg, 70.6 kg, 58.8 kg, 63.3 kg, 66.8 kg, 60.2 kg

It can be seen that the above data is close to each other.

So, mean will be calculated as an appropriate measure of central tendency.

Solution (II) :

Example: Salary is given.

Salary

In this case, there are some observations which are very far from other observations.

Therefore, here median will be calculated as an appropriate measure of central tendency.

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