Question

Find the arithmetic mean of the following data : [2 MARKS]

(a) 2, 3, 4, 5, 6, 7, 8, 9
(b) 12,13,14,15,16,17,18,19, 20

Answer 1

Each part: 1 Mark

The arithmetic mean is,

$\text{Mean}=\frac{\text{Sum of all observations}}{\text{Total number of observations}}$

(a) $\text{Mean}=\frac{2+3+4+5+6+7+8+9}{8}$

$\Rightarrow \text{Mean}=\frac{44}{8}=5.5$

(b) $\text{Mean}=\frac{12+13+14+15+16+17+18+19+20}{8}$

$\Rightarrow \text{Mean}=\frac{144}{9}=16$