HP 33S, User Manual

Page: 146 / 388

11–2
Statistical Operations
File name 33s-English-Manual-040130-Publication(Edition 2).doc Page : 388
Printed Date : 2004/1/30 Size : 13.7 x 21.2 cm
Entering One–Variable Data
1. Press
¹ ¡
{
Σ
} to clear existing statistical data.
2. Key in each x –value and press
/
.
3. The display shows n , the number of statistical data values now accumulated.
Pressing
/
actually enters two variables into the statistics registers because the
value already in the Y–register is accumulated as the y –value. For this reason, the
calculator will perform linear regression and show you values based on
y
even
when you have entered only x –data — or even if you have entered an unequal
number of x –and y –values. No error occurs, but the results are obviously not
meaningful.
To recall a value to the display immediately after it has been entered, press
¹
Í
.
Entering Two–Variable Data
In RPN mode, when your data consist of two variables, x is the independent
variable and y is the dependent variable . Remember to enter an ( x , y ) pair in
reverse order
(
y
Ï
x
) so that
y
ends up in the Y–register and X in the
X–register.
1. Press
¹ ¡
{
Σ
} to clear existing statistical data.
2. Key in the y –value first and press
Ï
.
3. Key in the corresponding x –value and press
/
.
4. The display shows n , the number of statistical data pairs you have
accumulated.
5.
Continue entering
x
,
y
–pairs.
n
is updated with each entry.
To recall an x –value to the display immediately after it has been entered, press
¹ Í
.
Correcting Errors in Data Entry
If you make a mistake when entering statistical data, delete the incorrect data and
add the correct data. Even if only one value of an
x , y –pair is incorrect, you must
delete and reenter both values.
To correct statistical data: