RS Aggarwal Solutions: Collection and Organisation of Data(Mean, Median and Mode) | Mathematics (Maths) Class 7 PDF Download

 Page 1


Q u e s t i o n : 1
Define the terms:
i
Data
ii
Raw data
iii
Array
iv
Tabulation of data
v
Observations
vi
Frequency of an observation
vii
Statistics
S o l u t i o n :
i
Data: Information in the form of numerical figures is known as data.
ii
Raw data: Data that is obtained in the original form is known as raw data.
iii
Array: When the raw data is obtained in ascending or descending order of magnitude, it is known as array.
iv
Tabulation of data: Arranging the data in a systematic way in the form of a table is known as the tabulation of the data.
v
Observations: Each numerical figure in a data is known as an observation.
vi
Frequency of an observation: Number of times an observation occurs in the data is known as the frequency of an observation.
vii
Statistics: The subject that deals with the collection, presentation, analysis and interpretation of the numerical data is known as statistics.
Q u e s t i o n : 2
A die was thrown 20 times and the following outcomes were recorded:
5, 2, 1, 3, 4, 4, 5, 6, 2, 2, 4, 5, 5, 6, 2, 2,4, 5, 5, 1.
Arrange the above data in ascending order and prepare the frequency table.
S o l u t i o n :
Data in the ascending order:
1, 1, 2, 2, 2, 2, 2, 3, 4, 4, 4, 4, 5, 5, 5, 5, 5, 5, 6, 6
Q u e s t i o n : 3
The daily wages inRs
of 15 workers in a factory are given below.
200, 180, 150, 150, 130, 180, 180, 200, 150, 130, 180, 180, 200, 150, 180.
Arrange the above data in ascending order and prepare the frequency table.
S o l u t i o n :
Daily wages in the ascending order:
130, 130, 150, 150, 150, 150, 180, 180, 180, 180, 180, 180, 200, 200, 200
Frequency table:
Q u e s t i o n : 4
Write the data given below in ascending order and prepare the frequency table.
7, 8, 7, 10, 6, 8, 9, 7, 10, 5, 7, 6, 8, 5, 6, 7, 8, 9, 7, 6, 7, 8.
S o l u t i o n :
Data in ascending order:
5, 5, 6, 6, 6, 6, 7, 7, 7, 7, 7, 7, 7, 8, 8, 8, 8, 8, 9, 9, 10, 10
Frequency table:
Page 2


Q u e s t i o n : 1
Define the terms:
i
Data
ii
Raw data
iii
Array
iv
Tabulation of data
v
Observations
vi
Frequency of an observation
vii
Statistics
S o l u t i o n :
i
Data: Information in the form of numerical figures is known as data.
ii
Raw data: Data that is obtained in the original form is known as raw data.
iii
Array: When the raw data is obtained in ascending or descending order of magnitude, it is known as array.
iv
Tabulation of data: Arranging the data in a systematic way in the form of a table is known as the tabulation of the data.
v
Observations: Each numerical figure in a data is known as an observation.
vi
Frequency of an observation: Number of times an observation occurs in the data is known as the frequency of an observation.
vii
Statistics: The subject that deals with the collection, presentation, analysis and interpretation of the numerical data is known as statistics.
Q u e s t i o n : 2
A die was thrown 20 times and the following outcomes were recorded:
5, 2, 1, 3, 4, 4, 5, 6, 2, 2, 4, 5, 5, 6, 2, 2,4, 5, 5, 1.
Arrange the above data in ascending order and prepare the frequency table.
S o l u t i o n :
Data in the ascending order:
1, 1, 2, 2, 2, 2, 2, 3, 4, 4, 4, 4, 5, 5, 5, 5, 5, 5, 6, 6
Q u e s t i o n : 3
The daily wages inRs
of 15 workers in a factory are given below.
200, 180, 150, 150, 130, 180, 180, 200, 150, 130, 180, 180, 200, 150, 180.
Arrange the above data in ascending order and prepare the frequency table.
S o l u t i o n :
Daily wages in the ascending order:
130, 130, 150, 150, 150, 150, 180, 180, 180, 180, 180, 180, 200, 200, 200
Frequency table:
Q u e s t i o n : 4
Write the data given below in ascending order and prepare the frequency table.
7, 8, 7, 10, 6, 8, 9, 7, 10, 5, 7, 6, 8, 5, 6, 7, 8, 9, 7, 6, 7, 8.
S o l u t i o n :
Data in ascending order:
5, 5, 6, 6, 6, 6, 7, 7, 7, 7, 7, 7, 7, 8, 8, 8, 8, 8, 9, 9, 10, 10
Frequency table:
Q u e s t i o n : 5
Fill in the blanks:
i
Data means information in the form of ...... figures.
ii
Data obtained in the ..... form is called raw data.
iii
Arranging the numerical figures in ascending of descending order is called an ...... .
iv
The number of times a particular observation occurs is called its ...... of data.
v
Arranging the data in the form of a table is called ...... of data.
S o l u t i o n :
i
numerical
ii
original
iii
array
iv
frequency
v
tabulation
Q u e s t i o n : 6
Find the mean of first five natural numbers.
S o l u t i o n :
First five natural numbers are 1, 2, 3, 4 and 5.
Mean of the first five natural numbers =
Sum of the given observations
Number of given observations 
         =
1+2+3+4+5
5
=
15
5
= 3
Hence, mean of the first five natural numbers is 3.
Q u e s t i o n : 7
Find the mean of first six odd natural numbers.
S o l u t i o n :
First six odd natural numbers are 1, 3, 5, 7, 9 and 11.
Mean of the first six natural numbers = 
Sum of the given observations 
Number of the given observations 
                                                = 
1+3+5+7+9+11
6
=
36
6
= 6
Mean of the first six odd natural numbers is 6.
Q u e s t i o n : 8
Find the mean of first seven even natural numbers.
S o l u t i o n :
First seven even natural numbers are 2, 4, 6, 8, 10, 12 and 14.
Mean of the first seven even natural numbers =
Sum of the given observations 
Number of the given observations 
                                                              =
2+4+6+8+10+12+14
7
=
56
7
= 8
Mean of the first seven even natural numbers is 8.
Q u e s t i o n : 9
Find the mean of first five prime numbers.
S o l u t i o n :
First five prime numbers are 2, 3, 5, 7 and 11.
Mean of the first five prime numbers =
Sum of the given observations 
Number of the given observations 
                                                       =
2+3+5+7+11
5
=
28
5
= 5. 6
Mean of the first five prime numbers is 5.6.
Page 3


Q u e s t i o n : 1
Define the terms:
i
Data
ii
Raw data
iii
Array
iv
Tabulation of data
v
Observations
vi
Frequency of an observation
vii
Statistics
S o l u t i o n :
i
Data: Information in the form of numerical figures is known as data.
ii
Raw data: Data that is obtained in the original form is known as raw data.
iii
Array: When the raw data is obtained in ascending or descending order of magnitude, it is known as array.
iv
Tabulation of data: Arranging the data in a systematic way in the form of a table is known as the tabulation of the data.
v
Observations: Each numerical figure in a data is known as an observation.
vi
Frequency of an observation: Number of times an observation occurs in the data is known as the frequency of an observation.
vii
Statistics: The subject that deals with the collection, presentation, analysis and interpretation of the numerical data is known as statistics.
Q u e s t i o n : 2
A die was thrown 20 times and the following outcomes were recorded:
5, 2, 1, 3, 4, 4, 5, 6, 2, 2, 4, 5, 5, 6, 2, 2,4, 5, 5, 1.
Arrange the above data in ascending order and prepare the frequency table.
S o l u t i o n :
Data in the ascending order:
1, 1, 2, 2, 2, 2, 2, 3, 4, 4, 4, 4, 5, 5, 5, 5, 5, 5, 6, 6
Q u e s t i o n : 3
The daily wages inRs
of 15 workers in a factory are given below.
200, 180, 150, 150, 130, 180, 180, 200, 150, 130, 180, 180, 200, 150, 180.
Arrange the above data in ascending order and prepare the frequency table.
S o l u t i o n :
Daily wages in the ascending order:
130, 130, 150, 150, 150, 150, 180, 180, 180, 180, 180, 180, 200, 200, 200
Frequency table:
Q u e s t i o n : 4
Write the data given below in ascending order and prepare the frequency table.
7, 8, 7, 10, 6, 8, 9, 7, 10, 5, 7, 6, 8, 5, 6, 7, 8, 9, 7, 6, 7, 8.
S o l u t i o n :
Data in ascending order:
5, 5, 6, 6, 6, 6, 7, 7, 7, 7, 7, 7, 7, 8, 8, 8, 8, 8, 9, 9, 10, 10
Frequency table:
Q u e s t i o n : 5
Fill in the blanks:
i
Data means information in the form of ...... figures.
ii
Data obtained in the ..... form is called raw data.
iii
Arranging the numerical figures in ascending of descending order is called an ...... .
iv
The number of times a particular observation occurs is called its ...... of data.
v
Arranging the data in the form of a table is called ...... of data.
S o l u t i o n :
i
numerical
ii
original
iii
array
iv
frequency
v
tabulation
Q u e s t i o n : 6
Find the mean of first five natural numbers.
S o l u t i o n :
First five natural numbers are 1, 2, 3, 4 and 5.
Mean of the first five natural numbers =
Sum of the given observations
Number of given observations 
         =
1+2+3+4+5
5
=
15
5
= 3
Hence, mean of the first five natural numbers is 3.
Q u e s t i o n : 7
Find the mean of first six odd natural numbers.
S o l u t i o n :
First six odd natural numbers are 1, 3, 5, 7, 9 and 11.
Mean of the first six natural numbers = 
Sum of the given observations 
Number of the given observations 
                                                = 
1+3+5+7+9+11
6
=
36
6
= 6
Mean of the first six odd natural numbers is 6.
Q u e s t i o n : 8
Find the mean of first seven even natural numbers.
S o l u t i o n :
First seven even natural numbers are 2, 4, 6, 8, 10, 12 and 14.
Mean of the first seven even natural numbers =
Sum of the given observations 
Number of the given observations 
                                                              =
2+4+6+8+10+12+14
7
=
56
7
= 8
Mean of the first seven even natural numbers is 8.
Q u e s t i o n : 9
Find the mean of first five prime numbers.
S o l u t i o n :
First five prime numbers are 2, 3, 5, 7 and 11.
Mean of the first five prime numbers =
Sum of the given observations 
Number of the given observations 
                                                       =
2+3+5+7+11
5
=
28
5
= 5. 6
Mean of the first five prime numbers is 5.6.
Q u e s t i o n : 1 0
Find the mean of first six multiples of 5.
S o l u t i o n :
First six multiples of 5 are 5, 10, 15, 20, 25 and 30.
Mean of the first six multiples of 5 =
Sum of the given observations 
Number of the given observations 
                                                   
5+10+15+20+25+30
6
=
105
6
= 17. 5
Q u e s t i o n : 1 1
The following table shows the weights inkg
of 15 workers in a factory:
 
Weight inkg 60 63 66 72 75
Number of workers 4 5 3 1 2
Calculate the mean weight.
S o l u t i o n :
Mean weight =
S f i ×x i
Sf i
=
975
15
= 65 kg
Q u e s t i o n : 1 2
The daily wages inrupees
of 60 workers in a factory are given below:
 
Daily wages inRs 140 150 160 180 190
Number of workers 14 16 15 7 8
Find the mean daily wages.
S o l u t i o n :
Mean daily wages =
S f i ×x i
Sf i
=
9540
60
= Rs 159
Q u e s t i o n : 1 3
The heights incm
of 90 plants in a garden are given below:
 
Height incm 58 60 62 64 66 74
Number of plants 20 25 15 8 12 10
Find the mean height.
S o l u t i o n :
Mean height =
S f i ×x i
Sf i
=
5634
90
= 62. 6 cm
Q u e s t i o n : 1 4
The ages inyears
of 50 players of a school are given below:
 
Age inyears 14 15 16 17 18
Number of players 15 14 10 8 3
Find the mean age.
S o l u t i o n :
( )
( )
( )
Page 4


Q u e s t i o n : 1
Define the terms:
i
Data
ii
Raw data
iii
Array
iv
Tabulation of data
v
Observations
vi
Frequency of an observation
vii
Statistics
S o l u t i o n :
i
Data: Information in the form of numerical figures is known as data.
ii
Raw data: Data that is obtained in the original form is known as raw data.
iii
Array: When the raw data is obtained in ascending or descending order of magnitude, it is known as array.
iv
Tabulation of data: Arranging the data in a systematic way in the form of a table is known as the tabulation of the data.
v
Observations: Each numerical figure in a data is known as an observation.
vi
Frequency of an observation: Number of times an observation occurs in the data is known as the frequency of an observation.
vii
Statistics: The subject that deals with the collection, presentation, analysis and interpretation of the numerical data is known as statistics.
Q u e s t i o n : 2
A die was thrown 20 times and the following outcomes were recorded:
5, 2, 1, 3, 4, 4, 5, 6, 2, 2, 4, 5, 5, 6, 2, 2,4, 5, 5, 1.
Arrange the above data in ascending order and prepare the frequency table.
S o l u t i o n :
Data in the ascending order:
1, 1, 2, 2, 2, 2, 2, 3, 4, 4, 4, 4, 5, 5, 5, 5, 5, 5, 6, 6
Q u e s t i o n : 3
The daily wages inRs
of 15 workers in a factory are given below.
200, 180, 150, 150, 130, 180, 180, 200, 150, 130, 180, 180, 200, 150, 180.
Arrange the above data in ascending order and prepare the frequency table.
S o l u t i o n :
Daily wages in the ascending order:
130, 130, 150, 150, 150, 150, 180, 180, 180, 180, 180, 180, 200, 200, 200
Frequency table:
Q u e s t i o n : 4
Write the data given below in ascending order and prepare the frequency table.
7, 8, 7, 10, 6, 8, 9, 7, 10, 5, 7, 6, 8, 5, 6, 7, 8, 9, 7, 6, 7, 8.
S o l u t i o n :
Data in ascending order:
5, 5, 6, 6, 6, 6, 7, 7, 7, 7, 7, 7, 7, 8, 8, 8, 8, 8, 9, 9, 10, 10
Frequency table:
Q u e s t i o n : 5
Fill in the blanks:
i
Data means information in the form of ...... figures.
ii
Data obtained in the ..... form is called raw data.
iii
Arranging the numerical figures in ascending of descending order is called an ...... .
iv
The number of times a particular observation occurs is called its ...... of data.
v
Arranging the data in the form of a table is called ...... of data.
S o l u t i o n :
i
numerical
ii
original
iii
array
iv
frequency
v
tabulation
Q u e s t i o n : 6
Find the mean of first five natural numbers.
S o l u t i o n :
First five natural numbers are 1, 2, 3, 4 and 5.
Mean of the first five natural numbers =
Sum of the given observations
Number of given observations 
         =
1+2+3+4+5
5
=
15
5
= 3
Hence, mean of the first five natural numbers is 3.
Q u e s t i o n : 7
Find the mean of first six odd natural numbers.
S o l u t i o n :
First six odd natural numbers are 1, 3, 5, 7, 9 and 11.
Mean of the first six natural numbers = 
Sum of the given observations 
Number of the given observations 
                                                = 
1+3+5+7+9+11
6
=
36
6
= 6
Mean of the first six odd natural numbers is 6.
Q u e s t i o n : 8
Find the mean of first seven even natural numbers.
S o l u t i o n :
First seven even natural numbers are 2, 4, 6, 8, 10, 12 and 14.
Mean of the first seven even natural numbers =
Sum of the given observations 
Number of the given observations 
                                                              =
2+4+6+8+10+12+14
7
=
56
7
= 8
Mean of the first seven even natural numbers is 8.
Q u e s t i o n : 9
Find the mean of first five prime numbers.
S o l u t i o n :
First five prime numbers are 2, 3, 5, 7 and 11.
Mean of the first five prime numbers =
Sum of the given observations 
Number of the given observations 
                                                       =
2+3+5+7+11
5
=
28
5
= 5. 6
Mean of the first five prime numbers is 5.6.
Q u e s t i o n : 1 0
Find the mean of first six multiples of 5.
S o l u t i o n :
First six multiples of 5 are 5, 10, 15, 20, 25 and 30.
Mean of the first six multiples of 5 =
Sum of the given observations 
Number of the given observations 
                                                   
5+10+15+20+25+30
6
=
105
6
= 17. 5
Q u e s t i o n : 1 1
The following table shows the weights inkg
of 15 workers in a factory:
 
Weight inkg 60 63 66 72 75
Number of workers 4 5 3 1 2
Calculate the mean weight.
S o l u t i o n :
Mean weight =
S f i ×x i
Sf i
=
975
15
= 65 kg
Q u e s t i o n : 1 2
The daily wages inrupees
of 60 workers in a factory are given below:
 
Daily wages inRs 140 150 160 180 190
Number of workers 14 16 15 7 8
Find the mean daily wages.
S o l u t i o n :
Mean daily wages =
S f i ×x i
Sf i
=
9540
60
= Rs 159
Q u e s t i o n : 1 3
The heights incm
of 90 plants in a garden are given below:
 
Height incm 58 60 62 64 66 74
Number of plants 20 25 15 8 12 10
Find the mean height.
S o l u t i o n :
Mean height =
S f i ×x i
Sf i
=
5634
90
= 62. 6 cm
Q u e s t i o n : 1 4
The ages inyears
of 50 players of a school are given below:
 
Age inyears 14 15 16 17 18
Number of players 15 14 10 8 3
Find the mean age.
S o l u t i o n :
( )
( )
( )
Mean age =
S f i ×x i
Sf i
=
770
50
= 15. 4 years
Q u e s t i o n : 1 5
The heights incm
of 40 boys were measured and recorded and under:
 
Height incm 165 170 175 180
Number of boys 9 8 11 12
Find the mean height.
S o l u t i o n :
Mean height =
S f i ×x i
Sf i
=
6930
40
= 173. 25 cm
Q u e s t i o n : 1 6
Find the median of:
i
3, 11, 7, 2, 5, 9, 9, 2, 10
ii
9,25, 18, 15, 6, 16, 8, 22, 21
iii
21, 15, 6, 25, 18, 13, 20, 9, 16, 8, 22
S o l u t i o n :
We have to find the median of the following data.
i
  3, 11, 7, 2, 5, 9, 9, 2 and 10
Arranging them in ascending order:
 2, 2, 3, 5, 7, 9, 9, 10, 11
Number of terms, N= 9
It is an odd number.
Median =
N+1
2
th observation
Median=
9+1
2
th observation
Median = 5th observation
Median=7
ii
9, 25, 18, 15, 6, 16, 8, 22, 21
Arranging them in ascending order,
6, 8, 9, 15, 16, 18, 21, 22, 25
Number of terms, N=9
It is an odd number.
Median =
N+1
2
th observation
Median =
9+1
2
th observation
Median = 5th observation
Median=16
iii
21, 15, 6, 25, 18, 13, 20, 9, 16, 8, 22
Arranging them in ascending order:
( )
( )
( )
( )
( )
( )
Page 5


Q u e s t i o n : 1
Define the terms:
i
Data
ii
Raw data
iii
Array
iv
Tabulation of data
v
Observations
vi
Frequency of an observation
vii
Statistics
S o l u t i o n :
i
Data: Information in the form of numerical figures is known as data.
ii
Raw data: Data that is obtained in the original form is known as raw data.
iii
Array: When the raw data is obtained in ascending or descending order of magnitude, it is known as array.
iv
Tabulation of data: Arranging the data in a systematic way in the form of a table is known as the tabulation of the data.
v
Observations: Each numerical figure in a data is known as an observation.
vi
Frequency of an observation: Number of times an observation occurs in the data is known as the frequency of an observation.
vii
Statistics: The subject that deals with the collection, presentation, analysis and interpretation of the numerical data is known as statistics.
Q u e s t i o n : 2
A die was thrown 20 times and the following outcomes were recorded:
5, 2, 1, 3, 4, 4, 5, 6, 2, 2, 4, 5, 5, 6, 2, 2,4, 5, 5, 1.
Arrange the above data in ascending order and prepare the frequency table.
S o l u t i o n :
Data in the ascending order:
1, 1, 2, 2, 2, 2, 2, 3, 4, 4, 4, 4, 5, 5, 5, 5, 5, 5, 6, 6
Q u e s t i o n : 3
The daily wages inRs
of 15 workers in a factory are given below.
200, 180, 150, 150, 130, 180, 180, 200, 150, 130, 180, 180, 200, 150, 180.
Arrange the above data in ascending order and prepare the frequency table.
S o l u t i o n :
Daily wages in the ascending order:
130, 130, 150, 150, 150, 150, 180, 180, 180, 180, 180, 180, 200, 200, 200
Frequency table:
Q u e s t i o n : 4
Write the data given below in ascending order and prepare the frequency table.
7, 8, 7, 10, 6, 8, 9, 7, 10, 5, 7, 6, 8, 5, 6, 7, 8, 9, 7, 6, 7, 8.
S o l u t i o n :
Data in ascending order:
5, 5, 6, 6, 6, 6, 7, 7, 7, 7, 7, 7, 7, 8, 8, 8, 8, 8, 9, 9, 10, 10
Frequency table:
Q u e s t i o n : 5
Fill in the blanks:
i
Data means information in the form of ...... figures.
ii
Data obtained in the ..... form is called raw data.
iii
Arranging the numerical figures in ascending of descending order is called an ...... .
iv
The number of times a particular observation occurs is called its ...... of data.
v
Arranging the data in the form of a table is called ...... of data.
S o l u t i o n :
i
numerical
ii
original
iii
array
iv
frequency
v
tabulation
Q u e s t i o n : 6
Find the mean of first five natural numbers.
S o l u t i o n :
First five natural numbers are 1, 2, 3, 4 and 5.
Mean of the first five natural numbers =
Sum of the given observations
Number of given observations 
         =
1+2+3+4+5
5
=
15
5
= 3
Hence, mean of the first five natural numbers is 3.
Q u e s t i o n : 7
Find the mean of first six odd natural numbers.
S o l u t i o n :
First six odd natural numbers are 1, 3, 5, 7, 9 and 11.
Mean of the first six natural numbers = 
Sum of the given observations 
Number of the given observations 
                                                = 
1+3+5+7+9+11
6
=
36
6
= 6
Mean of the first six odd natural numbers is 6.
Q u e s t i o n : 8
Find the mean of first seven even natural numbers.
S o l u t i o n :
First seven even natural numbers are 2, 4, 6, 8, 10, 12 and 14.
Mean of the first seven even natural numbers =
Sum of the given observations 
Number of the given observations 
                                                              =
2+4+6+8+10+12+14
7
=
56
7
= 8
Mean of the first seven even natural numbers is 8.
Q u e s t i o n : 9
Find the mean of first five prime numbers.
S o l u t i o n :
First five prime numbers are 2, 3, 5, 7 and 11.
Mean of the first five prime numbers =
Sum of the given observations 
Number of the given observations 
                                                       =
2+3+5+7+11
5
=
28
5
= 5. 6
Mean of the first five prime numbers is 5.6.
Q u e s t i o n : 1 0
Find the mean of first six multiples of 5.
S o l u t i o n :
First six multiples of 5 are 5, 10, 15, 20, 25 and 30.
Mean of the first six multiples of 5 =
Sum of the given observations 
Number of the given observations 
                                                   
5+10+15+20+25+30
6
=
105
6
= 17. 5
Q u e s t i o n : 1 1
The following table shows the weights inkg
of 15 workers in a factory:
 
Weight inkg 60 63 66 72 75
Number of workers 4 5 3 1 2
Calculate the mean weight.
S o l u t i o n :
Mean weight =
S f i ×x i
Sf i
=
975
15
= 65 kg
Q u e s t i o n : 1 2
The daily wages inrupees
of 60 workers in a factory are given below:
 
Daily wages inRs 140 150 160 180 190
Number of workers 14 16 15 7 8
Find the mean daily wages.
S o l u t i o n :
Mean daily wages =
S f i ×x i
Sf i
=
9540
60
= Rs 159
Q u e s t i o n : 1 3
The heights incm
of 90 plants in a garden are given below:
 
Height incm 58 60 62 64 66 74
Number of plants 20 25 15 8 12 10
Find the mean height.
S o l u t i o n :
Mean height =
S f i ×x i
Sf i
=
5634
90
= 62. 6 cm
Q u e s t i o n : 1 4
The ages inyears
of 50 players of a school are given below:
 
Age inyears 14 15 16 17 18
Number of players 15 14 10 8 3
Find the mean age.
S o l u t i o n :
( )
( )
( )
Mean age =
S f i ×x i
Sf i
=
770
50
= 15. 4 years
Q u e s t i o n : 1 5
The heights incm
of 40 boys were measured and recorded and under:
 
Height incm 165 170 175 180
Number of boys 9 8 11 12
Find the mean height.
S o l u t i o n :
Mean height =
S f i ×x i
Sf i
=
6930
40
= 173. 25 cm
Q u e s t i o n : 1 6
Find the median of:
i
3, 11, 7, 2, 5, 9, 9, 2, 10
ii
9,25, 18, 15, 6, 16, 8, 22, 21
iii
21, 15, 6, 25, 18, 13, 20, 9, 16, 8, 22
S o l u t i o n :
We have to find the median of the following data.
i
  3, 11, 7, 2, 5, 9, 9, 2 and 10
Arranging them in ascending order:
 2, 2, 3, 5, 7, 9, 9, 10, 11
Number of terms, N= 9
It is an odd number.
Median =
N+1
2
th observation
Median=
9+1
2
th observation
Median = 5th observation
Median=7
ii
9, 25, 18, 15, 6, 16, 8, 22, 21
Arranging them in ascending order,
6, 8, 9, 15, 16, 18, 21, 22, 25
Number of terms, N=9
It is an odd number.
Median =
N+1
2
th observation
Median =
9+1
2
th observation
Median = 5th observation
Median=16
iii
21, 15, 6, 25, 18, 13, 20, 9, 16, 8, 22
Arranging them in ascending order:
( )
( )
( )
( )
( )
( )
6, 8, 9, 13, 15, 16, 18, 20, 21, 22, 25
Number of terms, N = 11
It is an odd number.
Median =
N+1
2
th observation
Median =
11+1
2
th observation
Median = 6th observation
Median=16
Q u e s t i o n : 1 7
Find the median of:
i
10, 32, 17, 19, 21, 22, 9, 35
ii
55, 60, 35, 51, 29, 63, 72, 91, 85, 82
S o l u t i o n :
We have to find the median of the following data.
i
10, 32, 17, 19, 21, 22, 9, 35
Arranging them in ascending  order:
9, 10, 17, 19, 21, 22, 32, 35
Number of terms, N = 8
 Median =
1
2
N
2
th observation +
N
2
+1 th observation
Median =
1
2
(4th observation +5th observation)
Median =
1
2
(19 +21) = 20
? Median= 20
ii
55, 60, 35, 51, 29, 63, 72, 91, 85, 82
Arranging them in ascending order:
29, 35, 51, 55, 60, 63, 72, 82, 85, 91
Number of terms, N =10
Median =
1
2
N
2
th observation +
N
2
+1 th observation
Median = 
1
2
(5th observation +6th observation)Median =
1
2
(60 +63) ? Median = 61. 5
Q u e s t i o n : 1 8
Find the median of first 15 odd numbers.
S o l u t i o n :
First 15 odd numbers are 1, 3, 5, 7, 9, 11, 13, 15, 17, 19, 21, 23, 25, 27 and 29.
Number of terms, N = 15
It is an odd number.
Median =
N+1
2
th observation
Median =
15+1
2
th observationMedian = 15
Q u e s t i o n : 1 9
Find the median of first 10 even numbers.
S o l u t i o n :
First 10 even numbers are 2, 4, 6, 8, 10, 12, 14, 16, 18 and 20.
Number of terms, N=10
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