Look at the power.examp and run.power.examp functions in the TeachingDemos package. Do these do what you want? If not you can look at the code in them to see how to fill part of the area under the curve.
Hope this helps, -- Gregory (Greg) L. Snow Ph.D. Statistical Data Center Intermountain Healthcare [EMAIL PROTECTED] (801) 408-8111 > -----Original Message----- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] On Behalf Of Nair, > Murlidharan T > Sent: Friday, August 03, 2007 8:46 AM > To: Stephen Tucker; r-help@stat.math.ethz.ch > Subject: Re: [R] t-distribution > > I am trying to shade the critical regions for normal > distribution with different means and making overlaps of the > plots to explain Type I and Type II errors. I tried the > following. If I calculate the z score and as I did below, can > I use it to pick regions from the original data? I think I am > making mistake by calculating the z scores for d$x, can > someone explain the mistake I am making? > > left<- -1.96 > right<- 1.96 > mu1<-rnorm(100000,20,5) > d<-(density(mu1)) > x.tmp<-d$x > y.tmp<-d$y > x<-x.tmp > y<-y.tmp > mu1z<-(x.tmp-mean(x.tmp))/sd(x.tmp) # is it correct? > a<-which(mu1z <=left) > b<-which(mu1z >=right) > plot(x.tmp,y.tmp, type="l") > polygon(x=c(x.tmp[a],rev(x.tmp[a])),y=c(y.tmp[a],rep(0,length( > y.tmp[a])) > ),col="gray90") > polygon(x=c(x.tmp[b],rev(x.tmp[b])),y=c(y.tmp[b],rep(0,length( > y.tmp[b])) > ),col="gray90") > > -----Original Message----- > From: Stephen Tucker [mailto:[EMAIL PROTECTED] > Sent: Thursday, August 02, 2007 3:11 PM > To: Nair, Murlidharan T; r-help@stat.math.ethz.ch > Subject: RE: [R] t-distribution > > yes, or > > p <- seq(0.001,0.999,,1000) > x <- qt(p,df=9) > y <- dt(x,df=9) > plot(x,y,type="l") > > f <- function(x,y,...) { > polygon(x=c(x,rev(x)),y=c(y,rep(0,length(y))),...) > } > with(data.frame(x,y)[x >= 2.3,],f(x,y,col="gray90")) > with(data.frame(x,y)[x <= -2.3,],f(x,y,col="gray90")) > > > --- "Nair, Murlidharan T" <[EMAIL PROTECTED]> wrote: > > > > > I tried doing it this way. > > > > left<--2.3 > > right<-2.3 > > p <- seq(0.001,0.999,,1000) > > x <- qt(p,df=9) > > y <- dt(x,df=9) > > plot(x,y,type="l") > > x.tmp<-x > > y.tmp<-y > > a<-which(x<=left) > > > polygon(x=c(x.tmp[a],rev(x.tmp[a])),y=c(y.tmp[a],rep(0,length( > y.tmp[a])) > ),col="gray90") > > b<-which(x>=right) > > > polygon(x=c(x.tmp[b],rev(x.tmp[b])),y=c(y.tmp[b],rep(0,length( > y.tmp[b])) > ),col="gray90") > > > > Please let me know if I have made any mistakes. > > Thanks ../Murli > > > > > > > > -----Original Message----- > > From: Richard M. Heiberger [mailto:[EMAIL PROTECTED] > > Sent: Thu 8/2/2007 10:25 AM > > To: Nair, Murlidharan T; Stephen Tucker; r-help@stat.math.ethz.ch > > Subject: Re: [R] t-distribution > > > > I believe you are looking for the functionality I have in the > > norm.curve function in the HH package. > > > > Download and install HH from CRAN and then look at > > > > example(norm.curve) > > > > > > > > > ______________________________________________________________ > __________ > ____________Ready for the edge of your seat? > Check out tonight's top picks on Yahoo! TV. > http://tv.yahoo.com/ > > ______________________________________________ > R-help@stat.math.ethz.ch mailing list > 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. > ______________________________________________ R-help@stat.math.ethz.ch mailing list 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.
