Write the variance of first n natural numbers.

Life of bulbs produced by two factories A and B are given below:

The bulbs of which factory are more consistent from the point of view of the length of life?

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?

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.

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).