The Mean:
One of the most general uses of statistics is the determination of the mean value of a set of measurements. The word "Mean" is the statistical word used to state the "average" value of a set of data. A mean is mathematically determined in the same way as the "average" of a group of numbers is determined.
The arithmetic mean of a set of N measurements, Xl, X2, X3, ..., XN is equivalent to the sum of the measurements divided through the number of data points, N. Mathematically, that is expressed by the subsequent equation:
![2167_Mean.png](https://www.expertsmind.com/CMSImages/2167_Mean.png)
where
x¯ = the mean
n = the number of values (data)
X1 = the first data point, x2 = the second data point,....xi = the ith data point
xi = the i data point, x1 = the first data point, x2 = the second data point, etc.
The symbol Sigma ( Σ ) is used to indicate summation, and i = 1 to n indicates that the values of xi from i = 1 to i = n are added. The sum is then divided by the number of terms added, n.