Hypothesis Testing We start with an example:
Status Quo: A type of automobile engine emits a mean of 100 mg of nitrogen oxides per second at 100 horsepower.
Proprosed alternative: A modification of the engine proposed to reduce the mean emission rate.
The automobile manufacturer will abandon the original engine and adopt the new engine design (at much cost to the manufacturer) if it can be demonstrated that the modified engine has a mean emission rate less than 100 mg/s.
Evidence: A sample of 50 modified engines are built and tested. The sample mean emission is mg/s.
per second at 100 horsepower.
mg/s.
is a parameter of the conceptual population of engines that would be built if the modification were put in place. The “92” is based only on a sample of 50, and