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#3 Consider the following regression that examines the wages of graduating economists: wage: = n + lmnki + at where rank is the rank ofthe school the student graduated from {lower is better) and wage is the wage in dollars per hour. A random sample of recent graduates was taken. a) What is the predicted sign on 1? Explain. b) Suppose that the R2 of the model is very poor; R2 = 0.01. What does this say about the potential to interpret causality in the model? c) Suppose that a government experiment sent students to schools ofdifferent ranks: that is, rank; is randomly assigned. Is the estimate of}?1 unbiased'.' Explain