Calculate the mean and the median of the numbers : 2, 1, 0, 3, 1, 2, 3, 4, 3, 5.

On arranging the numbers in ascending order we get,

0, 1, 1, 2, 2, 3, 3, 3, 4, 5.

Sum of terms = 0 + 1 + 1 + 2 + 2 + 3 + 3 + 3 + 4 + 5 = 24.

By definition,

$\text{Mean} = \dfrac{\text{Sum of terms}}{\text{No. of terms}} \\[1em] = \dfrac{24}{10} \\[1em] = 2.4$

Here, n (no. of observations) = 10, which is even.

$\therefore \text{Median} = \dfrac{\dfrac{n}{2} \text{th observation} + \big(\dfrac{n}{2} + 1\big)\text{ th observation}}{2} \\[1em] = \dfrac{\dfrac{10}{2} \text{th observation} + \big(\dfrac{10}{2} + 1\big)\text{ th observation}}{2} \\[1em] = \dfrac{\text{ 5th observation + 6th observation}}{2} \\[1em] = \dfrac{2 + 3}{2} \\[1em] = \dfrac{5}{2} \\[1em] = 2.5$

Hence, mean = 2.4 and median = 2.5