[R] finding x values to meet a y

[Uwe Ligges]

Antonio Olinto wrote:
> Hi,
> 
> I'd like to find which values of x will give me a y.
> 
> In other words, in the example of a gaussian curve, I want to find the values of
> x that will give me a density, let's say, of 0.02.
> 
> curve(((1/(sqrt(2*pi)*10))*exp(-((x-50)^2)/(2*10^2))),xlim=c(0,100))

Numerical optimization might help:

optimize(
   function(x) (1/(sqrt(2*pi)*10) * exp(-((x-50)^2)/(2*10^2)) - 0.02)^2,
   interval = c(0, 50))

Uwe Ligges

> Thanks for any help,
> 
> Antonio Olinto
> 
> 
> 
> 
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