Question 1

Question 1: Find variance and S.D. for the following set of numbers. 7, 11, 2, 4, 9, 6, 3, 7, 11, 2, 5, 8, 3, 6, 8, 8, 2, 6

Accepted Answer

Given data: 7, 11, 2, 4, 9, 6, 3, 7, 11, 2, 5, 8, 3, 6, 8, 8, 2, 6 The tabulated form of the above data is Calculation of variance and S.D.

Question 2

Question 2: Find variance and S.D. for the following set of numbers. 65, 77, 81, 98, 100, 80, 129

Accepted Answer

Step-by-step solution provided.

Question 3

Question 3: Compute variance and standard deviation for the following data:

Accepted Answer

Step-by-step solution provided.

Question 4

Question 4: Compute the variance and S.D.

Accepted Answer

Let u = Calculation of variance of u:

Question 5

Question 5: Following data gives ages of 100 students in a college. Calculate variance and S.D.

Accepted Answer

Let u =

Question 6

Question 6: Find mean, variance and S.D. of the following data.

Accepted Answer

Alternate Method: Let u = Calculation of variance of u:

Question 7

Question 7: Find the variance and S.D. of the following frequency distribution which gives the distribution of 200 plants according to their height.

Accepted Answer

Since data is not continuous, we have to make it continuous. Let u = Calculation of variance of u:

Question 8

Question 8: The mean of 5 observations is 4.8 and the variance is 6.56. If three of the five observations are 1, 3, and 8, find the other two observations.

Accepted Answer

= 4.8, Var (X) = 6.56, n = 5, x1 = 1, x2 = 3, x3 = 8 ……(given) Let the remaining two observations be x4 and x5. From (i), we get x5 = 5 or x5 = 7 ∴ The two numbers are 5 and 7.

Chapter 8 Measures of Dispersion Ex 8.2 Solutions