QUESTION 3 What happens to the width of a prediction interval if we increase the confidence level from 95 percent to 99 percent? O A. Interval width does not change O B. Interval become wider for positive dependent variables and narrower for negative dependent variables O C. Interval become wider O D. Interval becomes narrower QUESTION 4 Suppose we have estimated a linear regression model with four independent variables, and we add a fifth variable to the model. What are the possible outcomes for our measures of model goodness-of-fit? A. Both R2 and adjusted-R2 may decline O B. R2 does not decline and adjusted-R2 may increase or decrease O C. R2 does not decline and adjusted-R2 must increase O D. Both R2 and adjusted-R2 must increase