# Weighted Mean; Correcting Statistical Data - HP -22S Owner's Manual

Scientific calculator.

To recall a value to the display immediately after it has been entered,
press
.1
LAST
I.
Entering Data for Two-Variable Statistics or
Weighted Mean
To enter x,y-pairs of statistical data:
1. Clear any previously stored statistical data by pressing
.1
CLEAR
1
{I}.
2. Key in the first x-value and press
1
INPUT
I.
The HP-22S displays
the x-value followed by a colon (:).
3. Key in the corresponding y-value and press
1
~+
I.
The HP-22S
displays
n=
1.0000.
4. Continue entering x,y-pairs. The n-value is updated with each
entry.
To enter data for calculating the weighted mean, enter each data
value as x, and its corresponding weight as y.
Correcting Statistical Data
If incorrect data has been entered by pressing [El, it can be deleted using
• [EJ. Then, the correct value is added using [El.
If one value of anxJI-
pair is incorrect, you must delete and then re-enter both values.
To correct statistical data:
1. Key in the x-value to be deleted. If the data consists of XJI- pairs,
press
(INPUT 1
and then key in the y-value.
2. Press.
[EJ to delete the value(s).* The n-value is decreased by
l.
3. Enter the correct value or XJI-pair using
[El.
• []:=::I
does not delete rounding errors that may occur when incorrect values are entered into
the statistical registers. Thus, subsequent results for corrected data may be different than for
data that was entered correctly without having to use
[]:=::I.
However, the difference will not
be serious unless the incorrect data has a very large magnitude compared with the correct
values; in this case, you may want to clear the statistical registers and re-enter all the data.
5: Statistical Calculations
61