#### Sample statistic

A sample statistic is a formula that
allows the analyst to compute a number from a sample with the purpose of inference
about a given population. For
instance, the sample mean and the sample standard deviation.

##### Illustration

From a sample of 50 firms in Florida
we can calculate the mean annual salary of their CEO's and the sample standard
deviation to make inference about the salaries of CEO's in Florida. In this
example:

- Sample: the 50 firms (n=50)
- Population: all the firms in Florida
- Population mean: expected value
of CEO's salaries (unknown)
- Sample statistic: the formula
used to calculate the mean

mean = (Sum of 50
CEO's salaries) / 50

- Sample mean: the estimated value