Find the mean of first ten odd natural numbers.

Mean = $\dfrac{\text{Sum of all observations }}{\text{Number of all observations }}$

= $\dfrac{1 + 3 + 5 + 7 + 9 + 11 + 13 + 15 + 17 + 19}{10}$

= $\dfrac{100}{10}$

= 10

Hence, the mean of first ten odd natural numbers is 10.