[R] Your help plz - (statistical problem)

Spencer Graves
Fri, 22 Aug 2003 15:57:05 -0000

Have you considered "nls" and / or "optim"?

hope this helps.  spencer graves

K.V.ANANTHA PADMANABHA wrote:
> Hi David,
>
> Please help me out to resolve the following
> statistical problem.
>
> For the following data
>
> X         Y
> 0        21.5
> 0        21.78
> 0.03     21.5
> 0.09     16.3
> 0.27     9.9
> 0.81     6.13
> 2.43     5.17
>
> How to put the logistic curve was fitted for the
> following model
>
>           C
> Y = --------------
>       (1 + (X/X0)^b)
>
>
> Where Y is the total no. of juveniles per parent
> animals alive at the end of the test and X is the
> concentartion.
>
> C = the expected no. of juveniles when X = 0
> X0 = the EC50 in the population
> b = the slope parameter
>
>
>
> I expect the results as early as possible.
>
> Thanks & regards
>
> K.V.Anantha Padmanabha
> Rallis India Limited
>
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