Parameter hypothesis test

A hypothesis test formally tests if a population parameter is different to a hypothesized value.

The null hypothesis states that the parameter is equal to the hypothesized value, against the alternative hypothesis that it is not equal to (or less than, or greater than) the hypothesized value. When the test p-value is small, you can reject the null hypothesis and conclude the sample is not from a population with the parameter equal to the hypothesized value.