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Re: linear regression
Hi Gert,
A quick P.S. on Mick's response:
If you specify multi-dimensional arrays as input to regresst.jnl it computes the
slopes and intercepts for each point in x,y,z. For example, if
v_xyt -- is a time series of xy fields (Nx x Ny x Nt)
and
v_t -- is a single point time series (Nt)
then regressing v_xyt against v_t will yield slope and intercept results of
dimension Nx x Ny -- a regression result at each (x,y) coordinate.
- steve
========================
Gert van Dijken wrote:
> Hi all,
>
> I have some problems using the linear regression go-tools.
>
> My data set looks as follows:
>
> yes? show data
> currently SET data sets:
> 1> ./ozo_prod_diff.cdf (default)
> name title I J K L
> OZODIFF (OZO[D=map.79F.V2]-OZO[D=map.92 1:301 1:301 ... 1:153
> PRODDIFF (PROD79_MASK- PROD92_MASK)*100/ 1:301 1:301 ... 1:153
>
> I would like to find the equation of the best fit (and r^2) for each day
> (L) when I plot ozodiff vs. proddiff.
>
> What I tried was more or less the following, for example day 45:
> yes? plot/vs/l=45 ozodiff,proddiff
> yes? ! lots of points, but it looks like a pretty good linear correlation...
> yes? let q = ozodiff[l=45]
> yes? let p = proddiff[l=45]
> yes? go regresst
> yes? set grid q
> yes? list slope
>
> The problem is that 'slope', 'intercep' or 'rsquare' are not one point,
> but a 301x301 array. When I use 'go regressx' or 'go regressy' I get a
> 1x301 array. Using 'go regressz' also gives a 301x301 array.
>
> Am I using the wrong go-tool?
>
> Ferret version: ! Version 5.22 - 07/27/00
>
> Thanks,
>
> Gert
--
Steve Hankin
NOAA/PMEL, 7600 Sand Point Way NE, Seattle, WA 98115-0070
ph. (206) 526-6080 -- FAX (206) 526-6744
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