Selina Concise Mathematics Class 9 ICSE Solutions Statistics
Selina ICSE Solutions for Class 9 Maths Chapter 18 Statistics
Exercise 18(A)1.State, which of the following variables are continuous and which are discrete:
(a) Number of children in your class.
(b) Distance travelled by a car.
(c) Sizes of shoes.
(d) Time.
(e) Number of patients in a hospital.
Solution 1:
(a) Discrete variable.
(b) Continuous variable.
(c) Discrete variable.
(d) Continuous variable.
(e) Discrete variable.
2.Given below are the marks obtained by 30 students in an examination:
08
|
17
|
33
|
41
|
47
|
23
|
20
|
34
|
09
|
18
|
42
|
14
|
30
|
19
|
29
|
11
|
36
|
48
|
40
|
24
|
22
|
02
|
16
|
21
|
15
|
32
|
47
|
44
|
33
|
01
|
Taking class intervals 1 - 10, 11 - 20, ....., 41 - 50; make a frequency table for the above distribution.
Solution 2:
3.The marks of 24 candidates in the subject mathematics are given below:
45
|
48
|
15
|
23
|
30
|
35
|
40
|
11
|
29
|
0
|
3
|
12
|
48
|
50
|
18
|
30
|
15
|
30
|
11
|
42
|
23
|
2
|
3
|
44
|
The maximum marks are 50. Make a frequency distribution taking class intervals 0 - 10, 10-20, ......
Solution 3:
In this frequency distribution, the marks 30 are in the class of interval 30 – 40 and not in 20 – 30. Similarly, marks 40 are in the class of interval 40 – 50 and not in 30 – 40.
4.Fill in the blanks:
(a) A quantity which can very from one individual to another is called a .............
(b) Sizes of shoes are ........... variables.
(c) Daily temperatures is ........... variable.
(d) The range of the data 7, 13, 6, 25, 18, 20, 16 is ............
(e) In the class interval 35 - 46; the lower limit is .......... and upper limit is .........
(f) The class mark of class interval 22 - 29 is .......... .
Solution 4:
5.Find the actual lower class limits, upper class limits and the mid-values of the classes: 10 - 19, 20 - 29, 30 - 39 and 40 - 49.
Solution 5:
6.Find the actual lower and upper class limits and also the class marks of the classes:
1.1 - 2.0, 2.1 -3.0 and 3.1 - 4.0.
Solution 6:
7.Use the table given below to find:
(a) The actual class limits of the fourth class.
(b) The class boundaries of the sixth class.
(c) The class mark of the third class.
(d) The upper and lower limits of the fifth class.
(e) The size of the third class.
Class Interval
|
Frequency
|
30 - 34
|
7
|
35 - 39
|
10
|
40 - 44
|
12
|
45 - 49
|
13
|
50 - 54
|
8
|
55 - 59
|
4
|
Solution 7:
8.Construct a cumulative frequency distribution table from the frequency table given below:
(i)
Class Interval
|
Frequency
|
0 - 8
|
9
|
8 - 16
|
13
|
16 - 24
|
12
|
24 - 32
|
7
|
32 - 40
|
15
|
(ii)
Class Interval
|
Frequency
|
1 - 10
|
12
|
11 - 20
|
18
|
21 - 30
|
23
|
31 - 40
|
15
|
41 - 50
|
10
|
Solution 8:
9.Construct a frequency distribution table from the following cumulative frequency distribution:
(i)
Class Interval
|
Cumulative Frequency
|
10 - 19
|
8
|
20 - 29
|
19
|
30 - 39
|
23
|
40 - 49
|
30
|
(ii)
C.I.
|
C.F.
|
5 - 10
|
18
|
10 - 15
|
30
|
15 - 20
|
46
|
20 - 25
|
73
|
25 - 30
|
90
|
Solution 9:
10.Construct a frequency table from the following data:
Marks
|
No. of students
|
less than 10
|
6
|
less than 20
|
15
|
less than 30
|
30
|
less than 40
|
39
|
less than 50
|
53
|
less than 60
|
70
|
Solution 10:
11.Construct the frequency distribution table from the following cumulative frequency table:
Ages
|
No. of students
|
Below 4
|
0
|
Below 7
|
85
|
Below 10
|
140
|
Below 13
|
243
|
Below 16
|
300
|
(i) State the number of students in the age group 10 - 13.
(ii) State the age-group which has the least number of students.
Solution 11:
12.Fill in the blanks in the following table:
Class Interval
|
Frequency
|
Cumulative Frequency
|
25 - 34
|
......
|
15
|
35 - 44
|
......
|
28
|
45 - 54
|
21
|
......
|
55 - 64
|
16
|
......
|
65 - 74
|
......
|
73
|
75 - 84
|
12
|
......
|
Solution 12:
13.The value of
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upto 50 decimal place is
3.14159265358979323846264338327950288419716939937510
(i) Make a frequency distribution table of digits from 0 to 9 after the decimal place.
(ii) Which are the most and least occurring digits?
Solution 13:
Exercise 18(B)
1.Construct a frequency polygon for the following distribution:
Class-intervals
|
0 - 4
|
4 - 8
|
8 - 12
|
12 - 16
|
16 - 20
|
20 - 24
|
Frequency
|
4
|
7
|
10
|
15
|
11
|
6
|
Solution 1:
2.Construct a combined histogram and frequency polygon for the following frequency distribution:
Class-Intervals
|
10 - 20
|
20 - 30
|
30 - 40
|
40 - 50
|
50 - 60
|
Frequency
|
3
|
5
|
6
|
4
|
2
|
Solution 2:
3.Construct a frequency polygon for the following data:
Class-Intervals
|
10 - 14
|
15 - 19
|
20 - 24
|
25 - 29
|
30 - 34
|
Frequency
|
5
|
8
|
12
|
9
|
4
|
Solution 3:
4.The daily wages in a factory are distributed as follows:
Daily wages (in Rs.)
|
125 - 175
|
175 - 225
|
225 - 275
|
275 - 325
|
325 - 375
|
Number of workers
|
4
|
20
|
22
|
10
|
6
|
Draw a frequency polygon for this distribution.
Solution 4:
5.(i)Draw frequency polygons for each of the following frequency distribution:
(a) using histogram
(b) without using histogram
C.I
|
10 - 30
|
30 - 50
|
50 - 70
|
70 - 90
|
90 - 110
|
110 - 130
|
130 - 150
|
ƒ
|
4
|
7
|
5
|
9
|
5
|
6
|
4
|
Solution 5(i):
5.(ii)Draw frequency polygons for each of the following frequency distribution:
(a) using histogram
(b) without using histogram
C.I
|
5 - 15
|
15 - 25
|
25 - 35
|
35 - 45
|
45 - 55
|
55 - 65
|
ƒ
|
8
|
16
|
18
|
14
|
8
|
2
|
Solution 5(ii):
Selina Concise Mathematics Class 9 ICSE Maths Solutions Chapter 18 - Statistics