HP 50G, User Manual

Page: 581 / 887

Page 18-14
X-Col, Y-Col:
these options apply only when you have more than two
columns in the matrix
Σ
DAT. By default, the x column is
column 1, and the y column is column 2.
_
Σ
X _
Σ
Y…
: summary statistics that you can choose as results of this
program by checking the appropriate field using [
CHK]
when that field is selected.
Many of these summary statistics are used to calculate statistics of two variables
(x,y) that may be related by a function y = f(x). Therefore, this program can be
thought off as a companion to program
3. Fit data..
Example 1 – For the x-y data currently in
Σ
DAT, obtain all the summary statistics.
Θ
To access the summary stats… option, use:
‚Ù˜˜˜ @@@OK@@@
Θ
Select the column numbers corresponding to the x- and y-data, i.e., X-Col:
1, and Y-Col: 2.
Θ
Using the
@ CHK@
key select all the options for outputs, i.e., _
Σ
X, _
Σ
Y, etc.
Θ
Press
@@@OK@@@
to obtain the following results:
Σ
X: 24.2,
Σ
Y: 11.72,
Σ
X2: 148.54,
Σ
Y2: 26.6246,
Σ
XY: 12.602, N
Σ
:8
Calculation of percentiles
Percentiles are measures that divide a data set into 100 parts. The basic
procedure to calculate the 100
⋅
p-th Percentile (0 < p < 1) in a sample of size n
is as follows:
1. Order the n observations from smallest to largest.
2. Determine the product n
⋅
p
A. If n
⋅
p is not an integer, round it up to the next integer and find the
corresponding ordered value.
Note: There are two other applications under the STAT menu, namely,
5.
Hypth. tests..
and
6. Conf. Interval..
These two applications will be discussed
later in the chapter.