: In a regression analysis of on-the-job head injuries to warehouse laborers caused by failing objects.
Question 1 : In a regression analysis of on-the-job head injuries to warehouse laborers caused by failing objects. Y is measured of severity of the injury, X 1 is weight of the object, X 2 is the distance the object fell, X 3 record if a hard hat, bump hat, or no hat worn at the time of the accident.
- Write the no-interaction linear regression model.
- Interpret all the \(\beta \) ’s in the context of this question.
- State the null hypothesis and the alternative hypothesis in terms of 3s for the following two situations
- Does wearing a bump hat reduce the expected severity of injury as compared with wearing no protection? (Assuming X1 and X2 are held constant.)
- Wearing a hat or not has no influence on the expected severity of injury when X1 and X2 are held constant.
d. Write the interaction linear regression model and then re-do part (b).
Question 2 : Consider the following data set
| Age | |||
| Sex | Young | Middle | Old |
| Male | 9 | 12 | 18 |
| Female | 9 | 10 | 14 |
- Obtain the scatterplot and comment on the plot.
- Define the necessary dummy variables and write down the interaction linear regression model for this problem.
- Obtain the best fitted model.
- Test if interaction is significant or not (use 5% significance level for the test).
- Regardless of your result in part (d), at 1% level of significance, is sex an important variable? How about age?
Question 3 : The board directors of a professional association conducted a random sample survey of 13 members to assess the effects of several possible amounts of dues increase. The sample results follow. X denotes the dollar increase in annual dues posited in the survey interview and Y = 1 if the interviewee indicated that the membership will not be renewed at that amount of dues increase and 0 if the membership will be renewed.
| X | 30 | 30 | 30 | 35 | 35 | 35 | 40 | 40 | 45 | 45 | 45 | 50 | 50 |
| Y | 0 | 1 | 0 | 1 | 1 | 0 | 1 | 0 | 0 | 1 | 1 | 1 | 0 |
- Obtain the best simple linear regression model and interpret the estimated coefficients.
- Obtain the best fitted linear probability model and interpret the estimated coefficients.
c. Obtain the best logit model and interpret the estimated coefficients.
Deliverable: Word Document
