In this exercise you will:
A sociological experiment examined the way racial descent and gender influenced people’s helpfulness towards a stranger. The data, a \(2\times2\times2\times2\) array, is shown in the table below.
| Requestor | Respondents | ||||||||
| Female | Male | Total | |||||||
| Help | Refuse | Total | Help | Refuse | Total | Help | Refuse | Total | |
| English | |||||||||
| females | 23 | 0 | 23 | 24 | 3 | 27 | 47 | 3 | 50 |
| males | 20 | 4 | 24 | 21 | 5 | 26 | 41 | 9 | 50 |
| Asian | |||||||||
| females | 25 | 2 | 27 | 17 | 11 | 28 | 42 | 13 | 55 |
| males | 9 | 15 | 24 | 21 | 5 | 26 | 30 | 20 | 50 |
Students of similar age and dressed alike approached strangers in a busy shopping precinct and requested change for a phone call. If the stranger provided or looked for change the response was counted as helpful. Not replying or not looking were counted as unhelpful. The stranger’s gender was also noted. The data can be obtained using:
The students were either Asian or English, males or females.
What are the explanatory and response variables?
What is the minimal model for a Poisson/log analysis?
Starting with the minimal model add interactions until the deviance drops to a value consistent with random variation. Give an interpretation of this model.
Does your model make sense when you look just at the proportions in the table? In other words, how well could you have predicted the model without formal analysis?
You should compare your work with the solutions for this workshop.