The formula of mean median mode?

Answer 1

If you have n observations for a variable X: x1, x2, x3, ... xn thenMean = (x1 + x2 + x3 + ... + xn)/n

To find the median, put the Xs in order and find the middle one. If n is odd then it is the value of the X in the (n+1)/2 position. If n is even, then it is half the sum of the Xs in the n+2 and n/2+1 positions.

There is no formula for the mode. It is simply the value that is observed most often.