To do curve fitting and forecasting :

1.Enter the data into two SUM lists: one for the x-values and one for the y-values. Make sure each list has the same number of items so that the items are in matched pairs.

2.From the SUM menu, press to display a menu of SUM-list names. The current list is labeled unless named otherwise.

3.Press a menu key to select a list of x-values (independent variable).

4.Select a list of y-values (dependent variable).

5.Now you see the FRCST menu. Whichever curve-fitting model was used last is named in the display. If you want to select a different model, press , and then the menu key for the model.

6.To calculate the curve-fitting results, press, , and

.

7.To forecast (estimate) a value:

a.Key in the known value and press the menu key for that variable.

b.Press the menu key for the variable whose value you want to forecast.

Example: Curve Fitting. BJ’s Dahlia Garden advertises on a local radio station. For the past six weeks, the manager has kept records of the number of minutes of advertising that were purchased, and the sales for that week.

134 10: Running Total and Statistics

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