a) Prepare a timeseries plot of the data, and on the basis of what you see in the plot, write a brief paragraph in which you explain what patterns you think are present in the sales series. b) Smooth out seasonal inuences and irregular movement by calculating the center moving averages. Add the centered moving averages to the original data you plotted in part a. Has the process of calculating center moving averages been effective in smoothing out the seasonal and irregular uctuations in the data? Explain. c) Determine the degree of seasonality by calculating seasonal indexes for each quarter of the yean d) Develop a forecast for Ms Lynch for the four quarters of 1998