These are retail turnover data for supermarkets and grocery stores in New South Wales for the period August 2018 to June 2020.

(a) Use these data to develop forecasts for the above period using a 3-period MA.

(b) Use these data to develop forecasts for the above period using a 3-period weighted MA.

(c) Plot the forecasts of the two types of MA and the original time series. Comment on your results.

Year ................................................ Turnover ($ millions)
Aug. 18 .................................................. 2167.7
Sept. 18 ................................................  2111.5
Oct. 18 ..................................................  2200.2
Nov. 18 .................................................  2188.8
Dec. 18 .................................................  2425.6
Jan. 19 ..................................................  2231.5
Feb. 19 .................................................  2021.8
Mar. 19 .................................................  2267.2
Apr. 19 ..................................................  2117.1
May 19 .................................................  2186.5
June 19 .................................................  2104.6
Jul. 19 ...................................................  2155.7
Aug. 19 .................................................  2244.2
Sept. 19 ................................................  2157.0
Oct. 19 ..................................................  2299.5
Nov. 19 .................................................  2271.3
Dec. 19 .................................................  2612.8
Jan. 20 ..................................................  2423.2
Feb. 20 .................................................  2157.3
Mar. 20 .................................................  2371.2
Apr. 20 ..................................................  2287.6
May 20 ..................................................  2339.4
June 20 ..................................................  2238.0