16.52 Food safety: Fairs, fast food, restaurants.
CASE 16.2 Case 16.2 (page 16-10) describes a study of the attitudes of people attending outdoor fairs about the safety of the food served at such locations. It contains the responses of 303 people to several questions. The variables in this data set are (in order):
fsafety
| subject | hfair | sfair | sfast | srest | gender |
The variable “sfair” contains responses to the safety question described in Case 16.2. The variables “srest” and “sfast” contain responses to the same question asked about food served in restaurants and in fast-food chains. Explain carefully why we cannot use the Kruskal-Wallis test to see if there are systematic differences in perceptions of food safety in these three locations.