Question

what is the arithmetic mean of first five natural number?

Answer 1

$$\begin{gathered} \mathrm{The}\mathrm{first}5\mathrm{natural}\mathrm{numbers}\mathrm{are}: \\ 1,2,3,4,5 \\ \mathrm{Now},\mathrm{mean}\mathrm{of}\mathrm{observations}=\frac{\mathrm{sum}\mathrm{of}\mathrm{observations}}{\mathrm{number}\mathrm{of}\mathrm{observations}} \\ =\frac{1+2+3+4+5}{5} \\ =\frac{15}{5} \\ =3 \end{gathered}$$