# 10th Maths Chapter 8 Statistics and Probability Exercise 8.1

10th Standard Maths Chapter 8 Statistics and Probability Exercise 8.1 Guide. TN SSLC Samacheer Kalvi Guide Chapter 8 Exercise 8.1 Book Back Answers & Solutions. 10th All Subject Guide – Click Here. Class 1 to 12 All Subject Book Back Answers – Click Here.

### 1. Find the range and coefficient of the range of the following data.

• (i) 63, 89, 98, 125, 79, 108, 117, 68
• (ii) 43.5, 13.6, 18.9, 38.4, 61.4, 29.8

Solution:
Range R = L – S.

L – Largest value,
S – Smallest value.

(i) 63, 89, 98, 125, 79, 108, 117, 68.
Here L = 125
S = 63
∴ R = L – S = 125 – 63 = 62

### 2.If the range and the smallest value of a set of data are 36.8 and 13.4 respectively, then find the largest value.

Range = 36.8
Smallest value (S) = 13.4
Range = L – S
36.8 = L – 13.4
L = 36.8 + 13.4 = 50.2
Largest value = 50.2

### 3. Calculate the range of the following data.

Solution:
Here the largest value = 650
The smallest value =400
∴ Range = L – S = 650 – 400
= 250

Solution:

### 5. Find the variance and standard deviation of the wages of 9 workers given below:

₹ 310, ₹ 290, ₹ 320, ₹ 280, ₹ 300, ₹ 290, ₹ 320, ₹ 310, ₹ 280.
Solution:

Solution:

Solution:

### 8. If the standard deviation of data is 4.5 and if each value of the data is decreased by 5, then find the new standard deviation.

The standard deviation of the data = 4.5
Each data is decreased by 5
The new standard deviation = 4.5

### 9.If the standard deviation of data is 3.6 and each value of the data is divided by 3, then find the new variance and new standard deviation.

Solution:
If the standard deviation of a data is 3.6, and each of the data is divided by 3 then the new standard deviation is also divided by 3.
∴ The new standard deviation = $$\frac{3.6}{3}$$
= 1.2
The new variance = (standard deviation)2
$$=\sigma^{2}=1.2^{2}=1.44$$

### 10. The rainfall recorded in various places in five districts in a week is given below.

Find its standard deviation.
Solution:

### 11. In a study about viral fever, the number of people affected in a town were noted as

Find its standard deviation.
Solution:
Let the assumed mean A = 35, C = 10

### 12. The measurements of the diameters (in cms) of the plates prepared in a factory are given below. Find its standard deviation.

Solution:
Assumed mean A = 30.5, C = 4

### 13. The time taken by 50 students to complete a 100-meter race are given below. Find its standard deviation.

Solution:
Assumed mean A = 11, C = 1

Solution:

### 15. The mean and variance of seven observations are 8 and 16 respectively. If five of these are 2, 4, 10, 12, and 14, then find the remaining two observations.

Solution:

The given 5 numbers are 2, 4, a, b, 10, 12, and 14.
a, b are 6 and 8.