Assignment 24067

In this exercise we look again at the relationship between the look of instructors and their course evaluation. The dataset contains several variables, but for the purpose of this problem we are only considering course evaluations, beauty and age. Download the file at the following link. Open the file in Excel and estimate the following three linear regression models:
(A) COURSE_EVAL = beta0 beta1 * BEAUTY error
(B) COURSE_EVAL = beta0 beta1 * AGE error
(C) COURSE_EVAL = beta0 beta1 * BEAUTY beta2 * AGE error
COURSE_EVAL: average course evaluation of the instructor
BEAUTY: beauty index of the instructor (between -2 and 2 with 0 representing average look)
AGE: age (in years) of the instructors
Answer the following questions:
Vladimir and Igor are identical twins and they both happen to be teachers at the same university: based on model C, how much do you expect to be the difference in COURSE_EVAL between them?
Mario and Luigi are longtime college friends from the class of 1960 and they now happen to be teachers at the same university; Mario has always been considered the better looking of the two with a BEAUTY index of 1.9 while Luigi’s index is 1.5. Based on model C, Mario is expected to have (type HIGHER or LOWER) COURSE_EVAL relative to Luigi by
What is the estimated effect of BEAUTY on COURSE_EVAL in regression A?_____ and in regression C?______
Comparing the estimates for regression A and C, do you find evidence that regression A might suffer from omitted variable bias? (type YES or NO)
Comparing the estimated effect of AGE on COURSE_EVAL in regression B and C: do you find evidence that regression B might suffer from omitted variable bias? (type YES or NO) . Is the statistical significance (at 5%) of AGE in the two regressions different? (type YES or NO)
Professor Wang has a beauty index of -1.5 and is 54 year old. What is the predicted course evaluation by model C for Professor Wang?
Which model would you recommend (type A, B, or C)