Dear Ferret users,
I did a simple experiment to see a linear trend of 1-D time series.
The data is attached here.
What I did is something like this:
'use ssh.nc'
'let p = t[gt=sla]'
'let q = sla'
'go regress'
'plot/vs p,what'
The result is good and it shows a reasonable graphic.
However, when I check the value of "slope", I think it is not correct.
'list slope'
VARIABLE : PQVAR / PVAR
FILENAME : ssh.nc
TIME : 16-DEC-1992 12:00 to 16-DEC-2012 00:00
0.001568
'list intercep'
VARIABLE : QAVE - SLOPE*PAVE
FILENAME : ssh.nc
TIME : 16-DEC-1992 12:00 to 16-DEC-2012 00:00
-41.19
'list rsquare'
VARIABLE : (PQVAR*PQVAR) / (PVAR*QVAR)
FILENAME : ssh.nc
TIME : 16-DEC-1992 12:00 to 16-DEC-2012 00:00
0.4646
Then I check this simple calculation using an MS-Excell.
I found that the slope and intercept are different. Only RSQUARE is showing the similar result.
What I got in MS-Excell is:
slope = 0.0477
intercept = 69.284
And I think the results from MS-Excell are correct.
Any idea how to solve it?
Thanks.
Iskhaq
---------------------------------------------------------------- Dr. Iskhaq Iskandar Jurusan Fisika, Fakultas MIPA Universitas Sriwijaya Kampus Inderalaya, Ogan Ilir (OI) Sumatra Selatan, 30662 INDONESIA Phone: +62 (711) 580743 Fax: +62 (711) 580268 E-mail: iskhaq.iskandar@xxxxxxxxx http://iskhaq.wordpress.com/ ----------------------------------------------------------------