The assignment is worth 10% of the final course mark. Please be aware that by handing in the home assignment you implicitly acknowledge to have read and accepted the instructions for home assignments as described on the VHM 801 homepage.
The data for the assignment were collected in a study at a veterinary hospital. Some owners of cats submitted to the hospital were selected to fill out a questionnaire about their cat. We concentrate here on two questions: the level of exercise (low/high) (of the cat!) and the amount of dry feed (little/much) given to the cat. For both questions, the two possible answers were suitably defined in quantitative terms. Two sets of questionnaire data were collected, one for 50 castrated male cats with diseases of the urinary system, and one for another group of 24 castrated male cats submitted to the hospital for routine treatments not related to such diseases. The data are given in the table below.
| Cats with urinary diseases | Cats without urinary diseases | |||
|---|---|---|---|---|
| Exercise level | Exercise level | |||
| Amount of dry feed | low | high | low | high |
| little | 5 | 3 | 12 | 5 |
| much | 14 | 28 | 5 | 2 |
Files containing the complete data (including also the additional data described under 4. below) are available in Minitab format and also in comma-separated format, for import into Stata and other statistical software.
All three questions below should be answered. The same principles for documenting and discussing your analyses as in previous assignments apply. In particular, all statistical models and assumptions should be specified, and any specific conditions needed to apply the methods used should be discussed.