Pharmacist

A pharmacist has been monitoring sales of a certain over-the-counter pain reliever. Daily sales during the last 15 days were:
Day :                        1    2    3    4    5    6    7    8    9    10   11    12    13    14    15
Number sold:       36  38  42  44  48  49  50  49  52  48   52    55   54    56    57

a) By just looking at the plot of this time series which method would you suggest using to predict future sales – a liner trend eqation or trend adjusted exponential smoothing? Why?

b) If you learn that on some days the store ran out of this pain reliever, would that knowledge cause you any concern? Explain.

c) Assume that the data refer to demand rather than sales. Using trend-adjusted exponential smoothing with an initial forecast of 50 for day 8, an initial trend estimate of 2, and α=β=.3, develop forecasts for days 9 through 16.