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

Mathematics in ICSE Class 9 is one of the most challenging and trickiest subjects of all. It includes complex topics such as logarithms, expansions, indices and Pythagoras Theorem which are difficult to understand for an average student. TopperLearning provides study materials for ICSE Class 9 Mathematics to make the subject easy and help students to clear all their concepts. Our study materials comprise numerous video lessons, question banks, revision notes and sample papers which help achieve success in the examination.

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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 Question 15

The mean of 200 observations is 20. It is found that the value of 180 is wrongly copied as 280. Find the actual mean.

Solution 15 Question 16 Solution 16 Question 17 Solution 17 Question 18 Solution 18 Question 19

The following data has been arranged in ascending order.

0, 1, 2, 3, x + 1, x + 5, 20, 21, 26, 29.

Find the value of x, if the median is 5.

Solution 19 Question 20 Solution 20 ## Key Features of Study Materials for ICSE Class 9 Maths:

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