Test statistic
A test statistic is the point estimate of the parameter of interest, obtained
from a sample. It is also called the sample statistic.
For instance, if the analyst is interested in the mean of a certain
population the sample statistic is the sample mean, which is referred as the
test statistic. In order to perform a test of hypothesis this test statistic
is standardized. Therefore, the standardized test statistic for the mean of
the population becomes:
Standardized test statistic = (Sample mean - Value from Ho)/
Standard deviation of sample mean