Consider Intel€™s Revenues in Table 14.4.2.
a. Construct a time-series plot for this data set. Describe the seasonal and cyclic behavior that you see, as well as any evidence of irregular behavior.
b. Which quarter (1, 2, 3, or 4) appears to be Intel€™s best in terms of sales level, based on your plot in part a?
c. Is the seasonal pattern (in your graph for part a) consistent across the entire time period?
d. Calculate the moving average (using one year of data at a time) for this time series. Construct a time-series plot with both the data and the moving average.
e. Describe the cyclic behavior revealed by the moving average.
f. Find the seasonal index for each quarter. Do these values appear reasonable compared to the time-series plot of the data?
g. Find the seasonally adjusted sales corresponding to each of the original sales values. Construct a times-eries plot of this seasonally adjusted series.
h. Do you see an overall linear long-term trend up or down in these sales data? Would it be appropriate to use a regression line for forecasting this series?
i. Intel€™s revenue fell from 8.852 to 8.680 from the first to the second quarter of 2007. What happened to revenue on a seasonally adjusted basis?

TABLE 14.4.2 Quarterly Revenues for Intel Net Sales Net Sales (billions) Year 2006 2006 2006 2006 2007 2007 (billions) $8.940 8.009 8.739 9.694 8.852 8.680 Year 2007 2007 2008 2008 2008 2008 $10.090 10.712 9.673 9.470 10.217 8.226