Mean or Average or Arithmetic Mean or Mean

For Un-grouped Data

Note: Mean of first n natural numbers is (n+1)/2

Practice Questions

1. Find the arithmetic mean of the data 5, 6, 9, 10, 6, 6, 7.
2.The mean of 30 numbers is 150. It was detected on rechecking that one value of 165 was wrongly copied as 135. Find the correct mean?   [151] 
3.Ʃx = 100, n = 10 then find the mean of the data.[10]
4.Mean of a given data is 10.   5 is added to each of the observation.
    I. Mean do no change.
    II. New Mean is  15.  
    Which of the statement is TRUE? Support your answer.
5.Find the mean of first 'n' natural numbers.
6.Find the average of the following set of scores 567, 434,323,290,401. [JNV 2017 ] 
7.Find the average of the following numbers. 06,0,12,14,13        [JNV 2012 ]
8.The average of the height of 5 students having height 30,40,50,60,70 is      [JNV 2011]
9.Find the average of 3,5,7,8,9,    [[JNV 2000 ]
10. The average of first five even numbers is  [JNV 2001]
11.Find the average of 10,9,8,7 and 6  [JNV 1999 ]
12.The heights of 5 students are 140,135,142,138,140. Their average height is   [JNV 1998 ]
13.The average of the height of 5 students having height 40,50,60,70,80 is
14.The average of 4,5,3.5,7.5,9.5 and 6.5 is   [JNV 1997]
15.The average of 8,6,0,9 and 7 is  [JNV 1994]
16.The marks obtained by 10 students are 23,25,37,36,27,28,29,34,36,38. The average marks are  [JNV 1993]
17.The average of 5 consecutive  even numbers starting with is  [JNV 1995]
18.The arithmetic mean of the data: 4, 5, 9, 10,12 is;
19.The mean  of the scores   x-1, x, x+1  is .......   [AP SSC 2017J]

 Check your progress

 Check your progress-2

1. The arithmetic mean of following data is:

Observation

11

14

17

20

frequency

3

6

8

7
 (a)  14.8   (b)  15.6 (c)  16.4 (d) 17

Miscellaneous-I

1.The mean of 1, 7, 5, 3, 4 and 4 is m, the mean of 3, 2, 4, 2, 3, 3 and P is m–1 and median Q then the average of P and Q is   [TET cum TRT - 2018] 

For  Grouped Data (Class-X)  

1.If the mean of the following frequency distribution is 188, find the missing frequencies x and y, if the sum of all frequencies is 100 

Classes

0-80

80-160

160-240

240-320

320-400

Frequency

20

25

x

y

10

2.If the mean of the following distribution is 54, find the value of p.   [CBSE SQP]

Class Interval

0-20

20-40

40-60

60-80

80-100

Frequency

7

p

10

9

13

3.Find the mean and median of the following data:  [CBSE SQP ]

Class

85-90

90-95

95-100

100-105

105-110

110-115

Frequency

15

22

20

18

20

25

4.The monthly expenditure on milk in 200 families of a Housing Society is given below

Monthly Expenditure ( in Rs.)

1000-1500

1500-2000

2000-2500

2500-3000

3000-3500

3500-4000

4000-4500

4500-5000

No of Families

24

40

33

x

30

22

16

7

Find the value of x and also find the mean expenditure  [CBSE SQP ]

 Find the mean of the following frequency Distribution  [CBSE ]

Class

10-15

15-20

20-25

25-30

30-35

Frequency

4

10

5

6

5

 

 

Step Deviation Method

1.Find the mean using the step deviation method. [CBSE SQP ]

Class

0-10

10-20

20-30

30-40

40-50

Frequency

6

10

15

9

10

Miscellaneous-II

1.If the mode of the following distribution is 55, then find the value of 𝑥. Hence, find the mean. [CBSE SQP ]

Class Interval

0-15

15-30

30-45

45-60

60-75

75-90

Frequency

10

7

x

15

10

12

 

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