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Class 9 Maths NCERT Solution for statistics part 3



In this page we have NCERT book Solutions for Class 9th Maths:statistics for EXERCISE 3 . Hope you like them and do not forget to like , social share and comment at the end of the page.

 


Question 1

The following number of goals was scored by a team in a series of 10 matches:

2, 3, 4, 5, 0, 1, 3, 3, 4, 3

Find the mean, median and mode of these scores.

Solution:

Mean= (Sum of all 10 matches) /10

=(2+3+4+5+0+1+3+3+4+3)/10 

=2.8

Median:

We need to arrange the goals in increasing order

0,1,2,3,3,3,3,4,4,5

Since the number of terms is 10 (even)

Mode:

We need to arrange the goals in increasing order

0,1,2,3,3,3,3,4,4,5

Since 3 occurs becomes maximum times. It is the mode

 

 

Question 2.

In a mathematics test given to 15 students, the following marks (out of 100) are recorded:

41, 39, 48, 52, 46, 62, 54, 40, 96, 52, 98, 40, 42, 52, 60

Find the mean, median and mode of this data.

Solution :

Mean= (Sum of all 15 students) /15

=(41+39+48+52+46+62+54+40+96+52+98+40+42+52+60)/10 

=54.8

Median:

We need to arrange the data in increasing order

39,40,40,41,42,46,48,52,52,52,54,60,62,96,98

Since the number of terms is 15(odd)

Median= (n+1)/2=8 term=52

Mode:

52 occurs maximum times.So mode is 52

 

 

Question 3.

The following observations have been arranged in ascending order. If the median of the data is 63, find the value of x.

29, 32, 48, 50, x, x + 2, 72, 78, 84, 95

Solution:

The number of term is even

So

2x+2=126

x=62

 

 

 

Question 4.

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

Solution:

14 occurs maximum time,so mode is 14

 

Question 5.

Find the mean salary of 60 workers of a factory from the following table

Salary( in Rs)

Number of Workers

3000

16

4000

12

5000

10

6000

8

7000

6

8000

4

9000

3

10000

1

Total

60

 

Solution

 

x

f

fx

3000

16

48000

4000

12

48000

5000

10

50000

6000

8

48000

7000

6

42000

8000

4

32000

9000

3

27000

10000

1

10000

sum

60

305000

 

Mean = fx/f= 305000/60=5083.33

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