If the standard deviation of a variable X is σ, then the standard deviation of the variable is
A. a σ

B.

C.

D.

The sum and the sum of squares of length x (in cm) and weight y (in g) of 50 plant products are given below:

Which is more variable, the length or weight?

If x₁, x₂, ……, x_n are n values of a variable X and y₁, y₂, ……., y_n are n values of variable Y such that y_i = ax_i + b, i = 1,2, ……, n, then write Var(Y) in terms of Var(X).

The mean and variance of the heights and weights of the students of a class are given below:

Which shows more variability, heights or weights?

If the sum of the squares of deviations for 10 observations taken from their mean is 2.5, then write the value of standard deviation.

For a group of 200 candidates, the mean and standard deviations of scores were found to be 40 and 15 respectively. Later on it was discovered that the score of 43 was misread as 34. Find the correct mean and standard deviation.

The mean and standard deviation of 18 observations are found to be 7 and 4 respectively. On rechecking it was found that an observation 12 was misread as 21. Calculate the correct mean and standard deviation.

Following are the marks obtained, out of 100, by two students Ravi and Hashina in 10 tests:

Who is more intelligent and who is more consistent?

The mean and variance of five observations are 4.4 and 8.24 respectively. If three of these are 1, 2 and 6, find the other two observations.

The following results show the number of workers and the wages paid to them in two factories A and B of the same industry.

(i) Which firm pays a larger amount as monthly wages?

(ii) Which firm shows greater variability in individual wages?

Coefficient of variation of the two distributions are 60% and 80% respectively, and their standard deviations are 21 and 16 respectively. Find their arithmetic means.