Consider the following table, consisting of 20 observations of the variable y and time t. a. Plot

Question:

Consider the following table, consisting of 20 observations of the variable y and time t.

a. Plot the series along with the superimposed linear and quadratic trends. Which trend model do you think describes the data well?
b. Estimate a linear trend model and a quadratic trend model. Validate your guess from the graphs by comparing their adjusted R2.