[R] question with integrate function
Göran Broström
goran.brostrom at umu.se
Tue Feb 6 20:33:10 CET 2018
Hi Hanna,
your function is essentially zero outside a short interval around 9. And
the help page states: "If the function is approximately constant (in
particular, zero) over nearly all its range it is possible that the
result and error estimate may be seriously wrong."
You could try to integrate over a finite interval, say (7, 12).
Göran Broström
On 2018-02-06 19:40, li li wrote:
> Sorry. I meant in the previous email that the function h() is a monotone
> decreasing function. Thanks very much.
>
> 2018-02-06 13:32 GMT-05:00 li li <hannah.hlx at gmail.com>:
>
>> Hi all,
>> The function h below is a function of c and it should be a monotone
>> increasing function since the integrand is nonnegative and integral is
>> taken from c to infinity. However, as we can see from the plot, it is not
>> shown to be monotone. Something wrong with the usage of integrate function?
>> Thanks so much for your help.
>> Hanna
>>
>>
>>
>> h <- function(c){
>> g <- function(x){pnorm(x-8.8, mean=0.4, sd=0.3,
>> lower.tail=TRUE)*dnorm(x, mean=9,sd=0.15)}
>> integrate(g, lower=c, upper=Inf)$value}
>>
>> xx <- seq(-20,20,by=0.001)
>> y <- xx
>> for (i in 1:length(xx)){y[i] <- h(xx[i])}
>> plot(xx, y)
>>
>>
>
> [[alternative HTML version deleted]]
>
> ______________________________________________
> R-help at r-project.org mailing list -- To UNSUBSCRIBE and more, see
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
>
More information about the R-help
mailing list