Sample Mean

Sample mean is the mean of the random sample values drawn from a population. It is denoted by  x?. Consider n independent random variables X1, X2, . . . Xn, each corresponding to a randomly selected observation. The formula for sample mean is:

For example, Suppose you have the following set of numbers from a population: 12, 13, 43, 55, 56, 67, 78, 79, 90. Then the  sample mean is

(12 + 13 + 43 + 55 + 56 + 67 + 78 + 79 + 90) / 9 = 54.78