A psychologist at a private mental hospital was asked

1. A psychologist at a private mental hospital was asked to determine whether there was any clear difference in the length of stay of patients with different categories of diagnosis. Looking at the last four patients in each of three major categories, the results (in terms of weeks of stay) were as follows:

Diagnosis Category

Affective Disorders                      Cognitive Disorders                 Drug-related Conditions

7                                                                  12                                                8

6                                                                    8                                              10

5                                                                    9                                              12

6                                                                  11                                              10

1. State the null and alternative hypothesis

2. Using a = 0.05, conduct the ANOVA.

3. What do you conclude?

4. Write out your source table