Gujarat Board Statistics Class 11 GSEB Solutions Chapter 4 Measures of Dispersion Ex 4.4 Textbook Exercise Questions and Answers.
Gujarat Board Textbook Solutions Class 11 Statistics Chapter 4 Measures of Dispersion Ex 4.4
Question 1.
The marks obtained by 9 students in a test of 100 marks in Mathematics are given below:
64, 63, 72, 65, 68, 69, 66, 67, 69
Find the standard deviation of marks obtained by the students.
Answer:
Here n = 9
Mean:
x̄ =
Standard deviation of marks:
s =
=
=
= 2.67 marks
Question 2.
The numbers of cars coming for service in five service stations of a company on a particular day are 7, 3, 11, 8, 9. Calculate the standard deviation of number of cars coming at the service station.
Answer:
Here, n = 5
Mean:
x̄ =
=
= 7.6 Cars
Standard deviation of number of cars for service:
S =
=
=
= 2.65 cars
Question 3.
The following frequency distribution represents the amounts of deposits and the number of depositors in a bank. Find the coefficient of standard deviation of the deposits.
Answer:
Mean:
x̄ = A +
= 20 –
= 20 – 1
= ₹ 19 thousand
Standard deviation of amount of deposites:
s =
=
=
=
Coefficient of standard deviation
=
Question 4.
The information of profits (in lakh ?) of 50 firms in the last year is given below. Find the standard deviation of the profit of the firms.
Answer:
Mean:
x̄ = A +
= 25 +
= 25 +
= 25 + 2.4
= ₹ 27.4 lakh
Standard deviation of profit:
Question 5.
Find the standard deviation of age of the persons from the following distribution of 125 persons living in a society. Also find the coefficient of standard deviation.
Answer:
Mean:
x̄ = A +
= 35 +
= 35 +
= 35 + 0.16
= 35.16
Standard deviation of age:
Coefficient of standard deviation of age
=