The data in the table below (and available online) representmonthly gross sales for Ska Brewing Company from 2009 to2012.  This is real data, let’s help Skaforecast 2013…
Year | January | February | March | April | May | June | July | August | September | October | November | December | Total |
9 9 | $193,481 | $170,674 | $228,095 | $232,372 | $288,188 | $304,763 | $337,825 | $342,121 | $320,011 | $304,756 | $221,514 | $235,591 | |
10 | $267,782 | $225,592 | $356,604 | $274,723 | $377,369 | $439,907 | $430,999 | $485,822 | $407,577 | $450,234 | $315,238 | $345,135 | |
11 | $319,313 | $323,726 | $342,353 | $361,315 | $612,500 | $564,599 | $518,422 | $623,860 | $412,091 | $530,636 | $313,034 | $395,686 | |
12 | $375,117 | $391,677 | $426,746 | $535,876 | $659,204 | $582,670 | $663,534 | $564,901 | $636,399 | $727,822 | $539,011 | $450,188 | |
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Slope | | | | | | | | | | | | | |
a)Sum up the totals for each year and fill inthe blanks above.
b)Forecast demand for each month and the totalfor 2013 using linear regression. Â
c)Graph the data, including the forecasts frompart b)in chronological ordertodisplay the seasonal pattern.  Printthisout and attach it.
d)Determine the slope for each month and fillin the blanks above.  According to the slopes, whichtwomonths are growing the fastest (at about thesame rate)?
e) Interpret i) the slope for the two fastestgrowing month(s) and ii) the annual slope.
Predict the twelve months of 2013 using all data at once withthe new =forecast.ets() function in Excel.
