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Class 9 RD SHARMA Solutions Maths Chapter 22 - Tabular Representation of Statistical Data

Tabular Representation of Statistical Data Exercise Ex. 22.1

Solution 1

Solution 2

Solution 3


Solution 4

The data obtained in original form are called raw data. Raw data does not give any useful information and is rather confusing to mind. Data is grouped so that it becomes understandable and can be interpreted. We form groups according to various characteristics. After grouping the data, we are in a position to make calculations of certain values which will help us in describing and analysing the data.

Solution 5

Solution 6

Solution 7

Solution 8

Solution 9

The final marks in mathematics of 30 students are as follows:

53,61,48,60,78,68,55,100,67,90,75,88,77,37,84,58,60,48,62,56,44,58,52,64,98,59,70,39,50,60

(i)


Group I(30-39) II(40-49) III(50-59) IV(60-69) V(70-79) VI(80-89) VII(90-99) VIII(100-109)
Observations 37, 39 44, 48, 48 50, 52, 53, 55, 56, 58, 58, 59 60, 60, 60, 61, 62, 64, 67, 68 70, 75, 77, 78 84, 88 90, 98 100



(ii) Highest score = 100

(iii) Lowest score = 37

(iv) Range = 100 - 37 = 63

(v) If 40 is the pass mark, 2 students have failed.

(vi) 8 students have scored 75 or more.

(vii) Observations 51, 54, 57 between 50 and 60 have not actually appeared.

(viii) 5 students have scored less than 50.


Solution 10

Solution 11

The numbers of runs scored by a player in 25 innings:

26, 35, 94, 48, 82, 105, 53, 0, 39, 42, 71, 0, 64, 15, 34, 67, 0, 42, 124, 84, 54, 48, 139, 64, 47.

(i) Runs in ascending order:- 0,0,0,15,26,34,35,39,42,42,47,48,48,53,54,64,64,67,71,82,84,94,105,124,139

(ii) The highest score = 139

(iii) The player did not score any run 3 times.

(iv) He scored 3 centuries.

(v) He scored more than 50 runs 12 times.

Solution 12

Solution 13

(i)



(ii)



(iii)


Solution 14

Number of children Tally marks Number of families
0 5
1 ll 7
2 ll 12
3 5
4 l 6
5 lll 3
6 lll 3

Solution 15

Marks Tally marks Frequency
20 - 30 l 1
30 - 40 lll 3
40 - 50 5
50 - 60 lll 8
60 - 70 lll 8
70 - 80 llll 9
80 - 90 llll 4
90 - 100 ll 2
Total = 40


Solution 16

Heights (in cm)
Tally marks Frequency
145 - 149 llll 4
150 - 154 llll 9
155 - 159 ll 12
160 - 164 5
    Total = 30



Solution 17

Height (in cm) Tally marks Frequency
800 - 810 lll 3
810 - 820 ll 2
820 - 830 l 1
830 - 840 lll 8
840 - 850 5
850 - 860 l 1
860 - 870 lll 3
870 - 880 l 1
880 - 890 l 1
890 - 900 5
Total = 30

Solution 18

Maximum temperature (in degree Celsius) Tally marks Frequency
20.0 - 21.0 l 6
21.0 - 22.0 5
22.0 - 23.0 llll 9
23.0 - 24.0 5
24.0 - 25.0 lll 3
25.0 - 26.0 ll 2
Total = 30

Solution 19

Monthly wages (in rupees) Tally marks Frequency
210 - 230 llll 4
230 - 250 llll 4
250 - 270 5
270 - 290 lll 3
290 - 310 ll 7
310 - 330 5
Total = 28

Solution 20

Here 9 students  have blood groups  A, 6 as B, 3 as AB and 12 as O.
So, the table representing the data is as follows:  

Blood group

Number of students

A

9

B

6

AB

3

O

12

Total

30



As 12 students have the blood group O and 3 have their blood group as AB. Clearly, the most common blood group among these students is O and the rarest blood group among these students is AB.

Solution 21

By observing the data given above following frequency distribution table can be constructed
 

Number of heads

Number of times (frequency)

0

 6

1

10

2

  9

3

  5

Total

30

Solution 22

(i) Class intervals will be 0 - 5, 5 - 10, 10 -15.....
    The grouped frequency distribution table is as follows:
    
                       

Hours

Number of children

0 - 5

10

5 - 10

13

10 - 15

 5

15 - 20

 2

Total

30

                                                                                         
(ii) The number of children, who watched TV for 15 or more hours a week
        is 2 (i.e. number of children in class interval 15 - 20).

Solution 23

Since first class interval is -19.9 to -15

Frequency distribution with lower limit included and upper limit excluded is:

Temperature Tally marks Frequency
-19.9 to -15 ll 2
-15 to -10.1  ll  7
-10.1 to -5.2   5
-5.2 to -0.3 llll 4
-0.3 to 4.6 ll 17
Total   35



Tabular Representation of Statistical Data Exercise Ex. 22.2

Solution 1

Solution 2

Solution 3


Solution 4



Age (in years): No. of patients Age (in years) Cumulative frequency
10 - 20 90 Less than 20 90
20 - 30 50 Less than 30 140
30 - 40 60 Less than 40 200
40 - 50 80 Less than 50 280
50 - 60 50 Less than 60 330
60 - 70 30 Less than 70 360
  N = 360    

Solution 5


Solution 6


Solution 7


Solution 8

(i)

Consumption (in kW) No. of Factories Class interval Frequency
Below 240 1 0 - 240 1
Below 270 4 240 - 270 4 - 1 = 3
Below 300 8 270 - 300 8 - 4 = 4
Below 330 24 300 - 330 24 - 8 = 16
Below 360 33 330 - 360 33 - 24 = 9
Below 390 38 360 - 390 38 - 33 = 5
Below 420 40 390 - 420 40 - 38 = 2


(ii)

 

Class interval Frequency Consumption (in kW) No. of factories
0 - 240 1 More than 0 40
240 - 270 3 More than 270 40 - 1 = 39
270 - 300 4 More than 270 39 - 3 = 36
300 - 330 16 More than 300 36 - 4 = 32
330 - 360 9 More than 330 32 - 16 = 16
360 - 390 5 More than 360 16 - 9 = 7
390 - 420 2 More than 390 7 - 5 = 2
    More than 420
2 - 2 = 0
  N = 40  
 


Solution 9


Tabular Representation of Statistical Data Exercise 22.26

Solution 1

When observations are large, it may not be easy to find the frequencies by simple counting.

So, we make use of tally marks.

Thus, Tally marks are used to find frequency.

Hence, correct option is (c).

Solution 2

The difference between the highest and lowest value of observations is called 'Range' of observations.

Hence, correct option is (c).

Solution 3

The difference between the upper class limit and the lower class limit is called class size.

Hence, correct option is (b).

Solution 4

Since, 10 - 20, 20 - 30 are Exclusive Class Intervals, the upper limit of a class is not included in the class.

Thus, 20, will be taken in the class 20 - 30.

Hence, correct option is (b).

Solution 5

begin mathsize 12px style Let space the space lower space limit space be space straight x.
Class space interval space equals space 4
rightwards double arrow Upper space limit space equals space straight x space plus space 4
Now comma space mid minus value space of space straight a space class space equals space fraction numerator straight x space plus space 4 space plus space straight x over denominator 2 end fraction equals straight x space plus space 2 space equals space 15 space left parenthesis given right parenthesis
rightwards double arrow straight x space equals space 13 space equals space lower space limit
Hence comma space correct space option space is space left parenthesis straight c right parenthesis. end style

Solution 6

begin mathsize 12px style Let space the space lower space limit space of space straight a space class space equals space straight x
Class space size space equals space 10
rightwards double arrow Upper space limit space equals space straight x space plus space 10
Now comma space mid minus value space equals space fraction numerator straight x space plus space 10 space plus space straight x over denominator 2 end fraction equals straight x space plus space 5 space equals space 42 space left parenthesis given right parenthesis
rightwards double arrow straight x space equals space 37 space equals space lower space limit
rightwards double arrow straight x space plus space 10 space equals space 47 space equals space upper space limit
Thus comma space upper space and space lower space limits space are space 47 comma space 37.
Hence comma space correct space option space is space left parenthesis straight a right parenthesis. space end style

Tabular Representation of Statistical Data Exercise 22.27

Solution 7

The number of times a particular item occurs in a given data is called its Frequency.

Hence, correct option is (b).

Solution 8

Number of classes = 9

Lower limit of the lowest class = 10.6

Width of each class = 2.5

So, Upper limit of the lowest class = 10.6 + 2.5 = 13.1

Now, Upper limit of the lowest class + Width of each class = Upper limit of the next class

Thus, we have

Upper limit of the lowest class + 8 × width of each class = Upper limit of the highest (9th) class

Upper limit of the highest (9th) class = 13.1 + 8 × 2.5 = 33.1

Hence, correct option is (b).

  

                                 

Solution 9

Range of observations = Highest observation - Lowest observation

                             = 95 - 62

                             = 33

Hence, correct option is (d).

Solution 10

Tally are usually marked in a bunch of 5: 4 in a vertical line and one is placed diagonally.

Hence, correct option is (c).

Solution 11

begin mathsize 12px style Let space the space class space size space equals space straight S
Lower space limit space space equals space straight l
rightwards double arrow Upper space limit space equals space straight l space plus space straight S
Now comma space mid minus point space equals space fraction numerator straight l space plus space straight l space plus space straight S over denominator 2 end fraction space equals space straight m space space left parenthesis given right parenthesis
rightwards double arrow straight S space equals space 2 straight m space minus space 2 straight l
Then comma space Upper space limit space equals space straight l space plus space straight S space equals space straight l space plus space 2 straight m space minus space 2 straight l space equals space 2 straight m space minus space straight l
Hence comma space correct space option space is space left parenthesis straight c right parenthesis. end style

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