These slides describe measures of dispersion properties. Very detail explanation on it. I hope students get more benefits about it.

1. Measures of Dispersion
Dr. Liaquat Ahmad
Associate Professor/Chairman
Department of Statistics and Computer Science

2. Properties of Variance
1. If the data values are identical in a set, then their variance will
be zero (0).
Var( C) = 0
2. Var(X + C) = Var(X), where C is a constant.
3. Var(X - C) = Var(X), where C is a constant.
4. Var(CX) = C2.Var(X), where C is a constant.
5. Var(X/C) =Var(X)/C2, where C is a constant.
6. Var(aX + b) = a2.Var(X), where a and b are constants.
7. If X1, X2,……., Xn are n independent random variables, then
Var(X1 + X2 +……+ Xn) = Var(X1) + Var(X2)
+……..+Var(Xn).

3. 1: If the data values are identical in a set, then their variance will
be zero (0). Var( C) = 0

4. Property 8.

7. Moments

17. Calculate first four Moments about
mean. Also calculate Coefficients of
Skewness, b1 and b2. Also interpret b1
and b2.

19. Example