# Is the sample mean equal to the population mean?

Sep 28, 2017

No

#### Explanation:

The sample is a part of the population that is chosen to estimate the whole population but obviously it can't. It belongs at the forecast statistic. A value obtained from the population belong at descrittive statistic and regards the whole "population". When you calculate the average square deviation you use two different formulation.
for a sample $s = \sqrt{\frac{\sum {\left(\overline{X} - \Xi\right)}^{2}}{n - 1}}$.
for a population: $s = \sqrt{\frac{\sum {\left(\overline{X} - \Xi\right)}^{2}}{n}}$
where $\overline{X}$ is the average value, $\Xi$ is the single value, $n$ is the number of the values mediated.