If the S.D. of a set of observations is 8 and if each observation is divided by -2, the S.D. of the new set of observations will be

Let x₁, x₂, ……x_n be values taken by a variable X and y₁, y₂, …….y_n be the values taken by a variable Y such that y_i = ax_i + b, i = 1,2, …….,, n. Then,

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

If two variates X and Y are connected by the relation , where a, b, c are constants such that ac < o, then

If for a sample of size 60, we have the following information and , then the variance is