Samacheer Kalvi 9th Maths Solutions Chapter 8 Statistics Ex 8.1

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Tamilnadu Samacheer Kalvi 9th Maths Chapter 8 Solutions Statistics Ex 8.1

Question 1.
In a week, temperature of a certain place is measured during winter are as follows 26°C, 24°C, 28°C, 31°C, 30°C, 26°C, 24°C. Find the mean temperature of the week.
Solution:
Samacheer Kalvi 9th Maths Chapter 8 Statistics Ex 8.1 1
Mean temperature of the week = 27°C
Samacheer Kalvi 9th Maths Solutions Chapter 8 Statistics Ex 8.1
Question 2.
The mean weight of 4 members of a family is 60kg. Three of them have the weight 56kg, 68kg and 72kg respectively. Find the weight of the fourth member.
Samacheer Kalvi 9th Maths Chapter 8 Statistics Ex 8.1 2
Solution:
Samacheer Kalvi 9th Maths Chapter 8 Statistics Ex 8.1 3
∴ The weight of the fourth member = 44 kg

Question 3.
In a class test in mathematics, 10 students scored 75 marks, 12 students scored 60 marks, 8 students scored 40 marks and 3 students scored 30 marks. Find the mean of their score.
Solution:
Total number of students = 10 + 12 + 8 + 3 = 33
Total score of 33 students = 10 × 75 + 12 × 60 + 8 × 40 + 3 × 30
= 750 + 720 + 320 + 90 = 1880
Samacheer Kalvi 9th Maths Chapter 8 Statistics Ex 8.1 4
= 56.96 or 57 approximately

Question 4.
In a research laboratory scientists treated 6 mice with lung cancer using natural medicine. Ten days later, they measured the volume of the tumor in each mouse and given the results in the table.
Samacheer Kalvi 9th Maths Chapter 8 Statistics Ex 8.1 5
Find the mean.
Solution:
Samacheer Kalvi 9th Maths Chapter 8 Statistics Ex 8.1 6
x = 142.5 mm3

Question 5.
If the mean of the following data is 20.2, then find the value of p
Samacheer Kalvi 9th Maths Chapter 8 Statistics Ex 8.1 7
Solution:
Samacheer Kalvi 9th Maths Chapter 8 Statistics Ex 8.1 8
(30 +p) 20.2 = 610+20p
606 +20.2p = 610+20p
20.2 p – 20p = 610 – 606 = 4
0.2 = 4

Samacheer Kalvi 9th Maths Chapter 8 Statistics Ex 8.1 50
Samacheer Kalvi 9th Maths Solutions Chapter 8 Statistics Ex 8.1
Question 6.
In the class, weight of students is measured for the class records. Calculate mean weight of the class students using Direct method.
Samacheer Kalvi 9th Maths Chapter 8 Statistics Ex 8.1 60
Solution:
Samacheer Kalvi 9th Maths Chapter 8 Statistics Ex 8.1 70

Question 7.
Calculate the mean of the following distribution using Assumed Mean Method:
Samacheer Kalvi 9th Maths Chapter 8 Statistics Ex 8.1 11
Solution:
Let Assumed mean be 25
Samacheer Kalvi 9th Maths Chapter 8 Statistics Ex 8.1 12

Question 8.
Find the Arithmetic Mean of the following data using Step Deviation Method
Samacheer Kalvi 9th Maths Chapter 8 Statistics Ex 8.1 13
Solution:
Standard Deviation Method
Samacheer Kalvi 9th Maths Chapter 8 Statistics Ex 8.1 14
Samacheer Kalvi 9th Maths Solutions Chapter 8 Statistics Ex 8.1

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