In the spreadsheet data set containing monthly S&P closing prices for the last 5 years

a. Calculate the 3-period moving average forecast, ending with September, 2019.

b. Find the weighted moving average forecast using weights 0.4, 0.5, and 0.6. .

c. Find the exponential smoothing forecast using alpha = 0.3 .

d. Do a trend analysis forecast.

e. Graph all the forecasts, along with the original data series, in the same graph. Which do you think is the most accurate?

f. Using MAD and MSE , determine the most accurate forecasting method.

Time 2 3 4 Sales 1 2 3 4 5 6 7 8 9 10 11 12 48 41 37 32 36 31 43 52 60 48 41 30