Gold has long been a very popular investment choice during times of economic crisis. This has resulted in a significant increase in the price of gold per ounce in recent years. The Excel file gold prices. xlsx shows the annual average price of an ounce of gold from 1997 to 2017.

a. Construct a graph showing the price per ounce of gold over time.

b. Forecast the average price of gold for 2018 using a trend projection.

c. Calculate the MAD for this forecast.

d. Check for the presence of positive auto-correlation.

e. Based on these results, does this forecasting method seem appropriate for these data?