The mean of 1 2 , 2 2 , 3 3 and 4 4 is:

Given,

Number of observations = 4

By formula,

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

Substituting values we get :

$$\begin{aligned}\text{Mean }= \frac{1^2 + 2^2 + 3^3 + 4^4}{4} \\[1em] = \frac{1 + 4 + 27 + 256}{4} \\[1em] = \frac{288}{4} \\[1em] = 72.\end{aligned}$$

Hence, option 2 is the correct option.