Chapter 9 Exercise 15

15. Using monthly sales of merchandise, forecast sales for the next three months.

This one could be answered using a data mining tool, but it is also easy within Excel. The main step is to build the query to obtain the data:
 
SELECT Format([SaleDate],"yyyy-mm") AS YearMonth,
Sum([SalePrice]*[Quantity]) AS Sales
FROM Sale INNER JOIN SaleItem ON Sale.SaleID = SaleItem.SaleID
GROUP BY Format([SaleDate],"yyyy-mm")
ORDER BY Format([SaleDate],"yyyy-mm");
 
Then copy the results into Excel, select the Sales data and drag the small square on the bottom right to do a simple regression. But there is not enough sample data to be realistic.