Find the mean of the first ten odd numbers.

First ten odd numbers are:

1, 3, 5, 7, 9, 11, 13, 15, 17, 19

Sum of observations = 1 + 3 + 5 + 7 + 9 + 11 + 13 + 15 + 17 + 19 = 100

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

= $\dfrac{100}{10}$ = 10.

Hence, mean of first ten odd numbers is 10.