134 10: Running Total and Statistics
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
E
)
—
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
)
œ
, and then the menu key for the model.
6.
To calculate the curve-fitting results,
press,
™
,
š
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.
