The mean deviation from the mean of the set of observation $$-1,0,4$$ is

Let an angle of a triangle is 60$$^\circ$$. If the variance of the angles of the triangle is 1014$$^\circ$$, then the other two angles are

For the random variable X with probability distribution is given by the table

The mean of X is

The mean and variance of $$n$$ observations $$x_1, x_2, x_3, \ldots . . x_n$$ are 5 and 0 respectively. If $$\sum_{i=1}^n x_i^2=400$$, then the value of $$n$$ is equal to