Concept explainers
Teacher pay and pupil performance. In Economic Policy (January 2011), researchers from the London School of Economics conducted a cross-country analysis of the relationship between teacher’s pay and pupils’ performance. Data collected for 39 countries were used to model y = the country’s average standardized score of its pupils. The independent variables under consideration were: x1 = country’s total teaching staff as a percentage of the country’s labor force, x2 = percentage of women on country’s total teaching staff, x3 = country’s pupil-teacher ratio, x4 = average teacher’s salary after 15 years on staff, x5 = average teaching hours per year, x6 = GDP growth of country (% ), x7 = country’s educational spending per year, and x8 = percentile position of country’s teachers’ salaries after 15 years on staff. Consider a stepwise regression run on the data.
- a. What is the form of the model fit in step 1? How many models are fit? How is the “best” independent variable selected in this step?
- b. What is the form of the model fit in step 2? How many models are fit? How is the “best” independent variable selected in this step?
- c. What is the form of the model fit in step 3? How many models are fit? How is the “best” independent variable selected in this step?
- d. The variables x3 , x4 , and x6 were deemed the best variables for predicting y. How do you recommend the researchers proceed from here? Why?
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