Chapter 22 : Statistics - Frank Solutions for Class 9 Maths ICSE

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Chapter 22 - Statistics Excercise Ex. 22.1

Question 1

Solution 1

Question 2

Solution 2

Question 3

Solution 3

Question 4

Solution 4

Question 5

Solution 5

Question 6

Find the actual (or true) lower and upper class limits and class-marks (or mid values) of the following classes: 2.1 - 4.0, 4.1 - 6.0 and 6.1 - 8.0.

Solution 6

Question 7

Observe the given frequency table to answer the following:

Class Interval	20-24	25-29	30-34	35-39	40-44	45-49
Frequency	6	12	10	15	9	2

a. The true class limits of the fifth class.

b. The size of the second class.

c. The class boundaries of the fourth class.

d. The upper and lower limits of the sixth class.

e. The class mark of the third class.

Solution 7

Question 8

Solution 8

Question 9

Solution 9

Question 10

Solution 10

Question 11

Solution 11

Question 12

Solution 12

Chapter 22 - Statistics Excercise Ex. 22.2

Question 1

Solution 1

Question 2

Solution 2

Question 3

Solution 3

Question 4

Solution 4

Question 5

Construct a frequency distribution table from the given cumulative frequency distribution showing the weights of 750 students in a school:

Weight (in kg)	c.f.
More Than 25	750
More Than 30	640
More Than 35	615
More Than 40	485
More Than 45	370
More Than 50	220
More Than 55	124
More Than 60	49
More Than 65	24
More Than 70	0

a. Find the number of students whose weight lie in the interval 40-45

b. Find the interval which has the most number of students.

Solution 5

Frequency distribution table is as follows:

Weight (in kg)	c.f.
25 - 30	110 (750 - 640)
30 - 35	25 (640 - 615)
35 - 40	130 (615 - 485)
40 - 45	115 (485 - 370)
45 - 50	150 (370 - 220)
50 - 55	96 (220 - 124)
55 - 60	75 (124 - 49)
60 - 65	25 (49 - 25)
65 - 70	24 (24 - 0)
70 - 75	0

a. The number of students whose weight lie in the interval 40 - 45 is 115.

b. The interval 45 - 50 has the most number of students.

Chapter 22 - Statistics Excercise Ex. 22.3

Question 1

Solution 1

Question 2

Solution 2

Question 3

Solution 3

Question 4

Solution 4

Question 5

Solution 5

Question 6

The daily maximum relative humidity (in per cent) in Mumbai from May 1 to May 7, 1992 is given below:

64, 70, 65, 80, 75, 78

Find the mean.

Solution 6

Question 7

Solution 7

Question 8

Solution 8

Question 9

Solution 9

Question 10

Solution 10

Question 11

Solution 11

Question 12

The mean of 16 natural numbers is 48. Find the resulting mean, if each of the number is

a. increased by 5

b. decreased by 8

c. multiplied by 4

d. divided by 0.25

e. increased by 50%

f. decreased by 10%

Solution 12

Question 13

The mean of 4 observations is 20. If one observation is excluded, the mean of the remaining observations becomes 15. Find the excluded observation.

Solution 13

Question 14

The mean monthly income of 8 men is Rs. 8079.75. A man whose monthly income is Rs. 8280 has also been taken into consideration. Calculate the mean monthly income of all the men.

Solution 14