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