Question

Find arithmetic mean of :9,10,12,15,18,20

Answer 1

Answer: Mean = 14.

Explanation:

$\overline{x} = \frac{1}{n} \sum_{i=i}^{n} x_{i}$

=> x bar = (9 + 10 + 12 + 15 + 18 + 20)/6

=> x bar = 84/6 = 14.

Some more properties:

• When we add a number to each observation, the mean also increases by that number. And this is same for subtraction of terms (mean becomes subtracted), division and multiplication (mean becomes divided and multiplied respectively by that factor).