Mean of n numbers X1, X2,--------Xn is m. If Xn is replaced by x the new mean is

To find the new mean when a number in a set is replaced with a new value, we can use the formula:

New mean = (Sum of all numbers - old number + new number) / Total number of numbers

In this case, we know the mean of n numbers X1, X2, ..., Xn is m. This means the sum of all these numbers is n * m.

If we replace Xn with a new value x, the sum of all the numbers would then be (n * m) - Xn + x.

The new mean can be calculated as:

New mean = [(n * m) - Xn + x] / n

This formula represents the average of the updated set of numbers.