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Section 6: Statistics Functions 77
File name: hp 12c_user's guide_English_HDPMBF12E44 Page: 77 of 209
Printered Date: 2005/7/29 Dimension: 14.8 cm x 21 cm
The table below shows where the accumulated statistics are stored.
Register Statistic
R
1
(and display) n: number of data pairs accumulated.
R
2
Σx: summation of x-values.
R
3
Σx
2
: summation of squares of x-values.
R
4
Σy: summation of y-values.
R
5
Σy
2
summation of squares of y-values.
R
6
Σxy: summation of products of x-values and y-values.
Correcting Accumulated Statistics
If you discover you have entered data incorrectly, the accumulated statistics can
easily be corrected:
z If the incorrect data point or data pair has just been entered and _ has
been pressed, press gFg^.
z If the incorrect data point or data pair is not the most recent one entered, key
in the incorrect data point or data pair again as if it were new, but press
g^ instead of _.
These operations cancel the effect of the incorrect data point or data pair. You can
then enter the data correctly, using
_
, just as if it were new.
Mean
Pressing
gÖ
calculates the means (arithmetic averages) of the x-values (
x
) and
of the y-values (
y
). The mean of the x-values appears in the display after
Ö
is
pressed; to display the mean of the y-values, press
~
.
Example:
A survey of seven salespersons in your company reveals that they work
the following hours a week and sell the following dollar volumes each month. How
many hours does the average salesperson work each week
?
How much does the
average salesperson sell each month
?