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/ ----------------------------------------------------------------
Attachment:
ssh.nc
Description: Cdf file