From: Dennis Shea <shea_at_nyahnyahspammersnyahnyah>

Date: Sat Jan 12 2013 - 10:59:23 MST

Date: Sat Jan 12 2013 - 10:59:23 MST

You do not "calculate (a) regression coefficient at (the) 95%

confidence level." You [1] calculate a regression coefficient;

then [2] test against the null hypothesis.

The example you sent is ambiguous.

What do printVarSummary(x) and printVarSummary(y) yield

If x(time,lat,lon) and y(time,lat,lon) then

rc = regCoef(x(lat|:,lon|:,time|:),y(lat|:,lon|:,time|:))

rc!0 = "lat" ; name dimensions

rc!1 = "lon"

rc&lat = y&lat" ; assign coordinate values to named dimensions

rc&lon = y&lon"

df = rc@nptxy-2 ; degrees of freedom

tval = rc@tval ; t-statistic

b = tval ; b must be same size as tval (and df)

b = 0.5

prob = betainc(df/(df+tval^2),df/2.0,b)

;copy_VarCoords(rc,prob)

;prob@long_name = "probability"

;prob@units = "fraction: [0,1]"

rc95 = where(prob.lt.0.95,rc@_FillValue,rc) ; **** note 0.95 ****

copy_VarCoords(rc, rc95)

printVarSummary(rc95)

On 1/11/13 6:36 AM, Xi Chang wrote:

*> Thanks for the response,
*

*> I think my way (codes) to calculate is still wrong.
*

*> Does anyone here has experince how to calculate regression coefficient
*

*> at 95% confidence level?
*

*>
*

*> I will really really appreciate if anyone can share their experience how to
*

*> calculate
*

*> it here.
*

*>
*

*> Regards,
*

*> Xi Chang.
*

*>
*

*>
*

*>
*

*>
*

*> On Fri, Jan 11, 2013 at 1:09 PM, Mary Haley <haley@ucar.edu> wrote:
*

*>
*

*>> Dear Xi,
*

*>>
*

*>> The error message is telling you that your argumens to the "where"
*

*>> function do not have the correct dimensions.
*

*>>
*

*>> In order to use the "where" function, he second and third arguments must
*

*>> either be the same dimensionality as the first argument, or else be scalars.
*

*>>
*

*>> My guess is that since "rc@_FillValue" is likely a scalar, and is
*

*>> probably okay, then "rc" is not the same dimensionality as "prob".
*

*>>
*

*>> -Mary
*

*>>
*

*>>
*

*>> On Jan 7, 2013, at 9:14 AM, Xi Chang wrote:
*

*>>
*

*>>> I really need a help, I want to plot the regression coeff at 95%
*

*>> confidence limit in 2D map.
*

*>>> ---[snip]
*

*>>> x = ispan(0,dimsizes(trmm&time)-1,1)*1.
*

*>>> rc = regCoef(x,trmm)
*

*>>> df = rc@nptxy-2 ; degrees of freedom
*

*>>> tval = rc@tval ; t-statistic
*

*>>> b = tval ; b must be same size as tval (and df)
*

*>>> b = 0.5
*

*>>> prob = (1 - betainc(df/(df+tval^2),df/2.0,b) )
*

*>>> copy_VarCoords(rc,prob)
*

*>>> rc95 = where(prob.lt.95,rc@_FillValue,rc)
*

*>>> --[snip]
*

*>>> plot = gsn_csm_contour_map_ce(wks,rc,res)
*

*>>>
*

*>>> but i got an error:
*

*>>> fatal:where: condition variable (parameter 1) dimension mismatch with
*

*>> parameter 2
*

*>>>
*

*>>> Anybody can give me some suggestions or maybe the codes are not correct
*

*>> (?).
*

*>>>
*

*>>> Thanks,
*

*>>> Xi Chang.
*

*>>>
*

*>>> _______________________________________________
*

*>>> ncl-talk mailing list
*

*>>> List instructions, subscriber options, unsubscribe:
*

*>>> http://mailman.ucar.edu/mailman/listinfo/ncl-talk
*

*>>
*

*>>
*

*>
*

*>
*

*>
*

*> _______________________________________________
*

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Received on Sat Jan 12 10:59:35 2013

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