Dear Dave,
Thankyou very much. With your outlined approach hopefully, I would get through.
Thanks once again.
Elisa


> From: lorenz@usgs.gov
> Date: Fri, 17 Jan 2014 08:52:38 -0600
> To: r-help@r-project.org
> Subject: Re: [R] predefined area under the curve
> 
> Elisa,
>   Part of the issue is that there is no unique solution. You could increase
> each of the 6 values by a fixed amount to make up the 0.242003 difference
> in area, or you could increase them proportionally, among many other
> schemes.
>   I'll outline an approach and you can decide how you want to proceed.
> 1.  Determine the contribution of reach point to the total area:
> matrix(diff(c(el[1,1], el[,1], el[12,1]), 2)/2)
> 2. The total contribution from the last 7 values is 1.42607687227.
> 3. To distribute the change equally over the last 7 values, simply add
> 0.242003/1.42607687227 = 0.1696984 to each of those 12 values.
> 4. To distribute unequally, you'll need to work that out yourself, but
> knowing the relative weights will be the key.
> Dave
> 
> 
> >Date: Thu, 16 Jan 2014 13:24:41 +0000
> >From: eliza botto <eliza_botto@hotmail.com>
> >To: "r-help@r-project.org" <r-help@r-project.org>
> >Subject: [R] predefined area under the curve
> >Message-ID: <BLU170-W1360C9AA25D48D8A388CBC689B90@phx.gbl>
> >Content-Type: text/plain
> >
> >Dear UseRs of R,
> >My sincere apologizes in advance if my question isn't relevant to the
> >operations in R. I actually have the following two columns data, with 12
> >rows in it.
> > dput(el)
> >
> >structure(c(-1.42607687227285, -1.0200762327862, -0.736315917376129,
> > -0.502402223373355, -0.293381232121193, -0.0965586152896391,
> > 0.0965586152896391, 0.293381232121194, 0.502402223373355,
> >0.73631591737613, 1.0200762327862, 1.42607687227285,
> >1.99095972340185, 1.84006682649012, 1.71563586990498,
> >1.60312301737773, 0.748443534297919, 0.696909774793038,
> >0.64586377528834, 0.594330015783459, 0.270606020696256,
> >0.242477807564444, 0.211370068418158, 0.173646844190226), .Dim =
> >c(12L, 2L), .Dimnames = list(    NULL, c("", "GG")))
> >
> >When I plot column 2 against column 1 , i get a curve with an area
> >[auc(column1,column2)] under it equals to 2.602997. As i am calibrating it
> >for further simulations therefore i know that the area under the curve
> should
> >actually be equal to 2.845. I also know that the first 6 rows have been
> >located accurately, therefore the rows from 7 to 12 need to be relocated
> in
> >such a manner that area under the curve gets equal to or as close as
> >possible to 2.845. How can I do that? i have been doing it manually but at
> >the cost of time and  accuracy.
> >
> >Thankyou very much in advance.
> >Elisa
> >       [[alternative HTML version deleted]]
> 
> 	[[alternative HTML version deleted]]
> 
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