Actual sales of a product are given as follows:

Forecast for the first period is 107. Assume smoothing constant = 0.7 and trend smoothing constant = 0.5.

i) Find the weighted moving average considering 3 recent last periods and giving weights of 0.40, 0.36 and 0.24.

ii) Forecast by exponential smoothing for each of the periods starting from the period 2 and onwards.

iii) Forecast by exponential smoothing including trend adjustment for the same periods (assume T1 = 0).

iv) Plot the actual sales given and identify the trend in the demand data.

v) Plot the forecasted sales in i), ii) and iii), and check which one is closer to the actual ones overall.

\begin{tabular}{clccccccc} \hline Period & 1 & 2 & 3 & 4 & 5 & 6 & 7 & 8 \\ Actual sales & 110 & 106 & 108 & 109 & 112 & 98 & 102 & 104 \end{tabular}