In Excel do Chapter $3-1,2($parts $1,2,4),8,23$

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Hint: This is explained on page $82$ of the text. Here is the explanation from the book

A simple but widely used approach to forecasting is the naive approach. A naive forecast uses a single previous value of a time series as the basis of a forecast. The naive approach can be used with a stable series $($variations around an average$),$ with seasonal variations, or with trend. With a stable series, the last data point becomes the forecast for the next period. Thus, if demand for a product last week was $20$ cases, the forecast for this week is $20$ cases. With seasonal variations, the forecast for this $$season$$ is equal to the value of the series last $$season$.$ For example, the forecast for demand for turkeys this Thanksgiving season is equal to demand for turkeys last Thanksgiving; the forecast of the number of checks cashed at a bank on the first day of the month next month is equal to the number of checks cashed on the first day of this month; and the forecast for highway traffic volume this Friday is equal to the highway traffic volume last Friday. For data with trend, the forecast is equal to the last value of the series plus or minus the difference between the last two page $83$values of the series.

So you have to determine which type of the three to use for each product based on whether it is stable, has a trend, or is seasonal, and then use the appropriate method described above for each of the products.

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