Hypothesis Tests

We are doing a test about a hypothesis and this hypothesis in this case is going to concentrate on a parameter of a population. That parameter is the population mean. Now, there are four variations of hypothesis tests. This case is testing a hypothesis with parameter of population mean and we know the standard deviation of the population which is σ because in the question it will be given and in the real world it will be available from data or computation.

We must know something really important before we start testing. It is about rejection region on the graph (e.g. normal distribution graph) or on a picture we could draw about from where to where we reject the null hypothesis because it is wrong and its alternative is true. Acceptance region is from where to where we accept the null hypothesis because it is right and its alternative is false on the graph or a picture.

The rejection region on a graph or a picture tells us about the probability of getting rid of null hypothesis. It is also called critical region. Acceptance region is the region of keeping null hypothesis. The critical point is the line separating these two regions.

rejection region

acceptance region

null hypothesis is not true in this region

null hypothesis is true in this region

alternative hypothesis is wrong in this region

alternative hypothesis is true in this region    DNA Pot (c) 2009 - Current

Review Concepts before testing: Rejection region