HP 30b Business Professional Calculator - Manual (Page 78)

Statistical Operations 70
The Data and Stats Menus
Statistics analysis functions are located in the Data and Statistics menus accessible with the
:y
and
:z
keys. See Figure 1 for assistance with navigating through the
menus.
Press
:y
to open the Data menu. In this menu, enter a list of x values for one-variable
statistics, a list of pairs, (x, F) for one-variable statistics with frequency, or a list of pairs, (x, y)
for two-variable statistics. To enter data, key in a number and press
I
.
Press
:z
to analyze the data. If you attempt to open the Statistics (Stats) menu before
entering data, you will be redirected to the Data menu. When opened, the Stats menu
displays 2 Vars for two-variable statistics. Press
I
repeatedly to select the type of
statistical operations desired, two-variable, (2 Vars), one-variable, (1 Var), or one-variable
with frequency (1 Freq).
After selecting the type of statistical operation you want, select a sub-menu by pressing
<
or
>
, and press
I
to open it. Once in a sub-menu, press
<
or
>
repeatedly to view the results. To return from the sub-menu to the Statistics menu, press
:z
.
NOTE: in one-variable modes, there are no items for y, and the Predictions sub-menu is not
available.
Pressing
I
with the Predictions sub-menu displayed opens a sub-menu, in which you
can choose among seven different types of regression lines. See Figure 1. To select a specific
type of regression line in the Predictions sub-menu, press
I
to cycle through the
options.
NOTE: if you press
=
, the calculator automatically selects the curve that is the best fit for
your data.
Once you select a regression line, press
<
to see the regression line parameters and
perform predictions.
Table 12-1 The Statistics Menu Items
Menu Item Description
Nb Item Number of items.
Mean
Average of x values.
Mean
Average of y values.
x Std. Dev Standard deviation for x : a measure of how dispersed the x data values are about
the mean.
X
Y