In Exercise 35, you investigated the federal rate on 3-month Treasury bills between 1950 and 1980. The scatterplot below shows that the trend changed dramatically after 1980, so we computed a new regression model for the years 1981 to 2013.

Here's the model for the data from 1981 to 2013:
Dependent variable is Rate
R-squared = 77.0% s = 1.626
Variable Coefficient
Intercept …………………. 18.87316
Year - 1950 ………………. -0.30317
a) How does this model compare to the one in Exercise 35?
b) What does this model estimate the interest rate was in 2000? How does this compare to the rate you predicted in Exercise 35?
c) Do you trust this newer predicted value? Explain.
d) What does each of the two models predict the interest rate on 3-month Treasury bills will be in 2020?
e) Comment on your predictions in d).