);
variability of scores within groups (s); sample size
(n); and alpha error (a). A dynamic applet allows
the user to manipulate a factor and immediately see the effect on other factors. Description: This exercise illustrates the relationship between
statistical power (the probability of rejecting a false null hypothesis) and
four features of the test situation: the size of the difference between the
actual mean and the hypothesized mean ();
variability of scores within groups (s); sample size
(n); and alpha error (a). A dynamic applet allows
the user to manipulate a factor and immediately see the effect on other factors.
What do I need to know? You should have an understanding of hypothesis testing procedures. You may want to complete the WISE Hypothesis Testing Tutorial prior to attempting the power tutorial. The examples in the power tutorial are similar to those used in the hypothesis testing tutorial. Also, you may want to review a description of the applet that you will be using.
What do I need? For this tutorial you will need a paper copy of the WISE Power lab exercise pages and access to the WISE Power applet. If you do not have a copy of the lab exercise, follow the link below for a printable version. Note: the printed exercise guides you through the lab.
Questions: You will be asked several questions and you will be given feedback regarding your answers. The end of the tutorial includes some "thought" questions.
Research Scenario: Training programs boast that their graduates score higher on average than the population of individuals who do not participate in a training course. We will examine results from several different training programs. Scores from each distribution in this tutorial are normally distributed.
Download a copy of the Exercise