• AKA sample mean
• Estimated mean is different from the population mean`
• Estimated mean is defined by $\overline{x}$ whereas population mean is defined by $\mu$

• If we use N rather than N-1 on the denominator we will underestimate the value of the mean.

Estimates the population Mean ($\mu$); its spread is Estimated Variance; the distribution of the sample mean is described by the Central Limit Theorem.