Agricultural production is heavily dependent on weather conditions, which is why most of the data collected on agriculture is focused on these factors. The lack of data on other influences, such as land quality, makes it difficult to form good estimates about the arable land allocation among different crops. The file Cereal contains the harvested area of cereal crops (in thousand hectares) for Portugal from 2009 to 2018.

a. Plot the data.

b. Compute a linear trend forecasting equation and plot the results.

c. Compute a quadratic trend forecasting equation and plot the results.

d. Compute an exponential trend forecasting equation and plot the results.

e. Using the forecasting equations in (b) through (d), what are your annual forecasts for the harvested area for 2019 and 2020?

f. How can you explain the differences in the three forecasts in (e)? What forecast do you think you should use? Why?