From: Charles Annis, P.E. <Charles.Annis_at_statisticalengineering.com>

Date: Wed 27 Sep 2006 - 16:34:49 GMT

lines(x, y2)

lines(x, y1)

polygon(c(-1.96,-1.96,x[161:1],-10), c(0,dnorm(-1.96,m=0), y1[161:1],0),

text(3, .2, quote(H[1]:~~mu[1]==mu[2]+delta))

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. Received on Thu Sep 28 02:50:20 2006

Date: Wed 27 Sep 2006 - 16:34:49 GMT

Isaac:

You will likely find something helpful here: http://addictedtor.free.fr/graphiques/thumbs.php

I also recently came across this code (I thought it was at the URL above, but I can't find it now) that may be useful with modification.

I apologize to the code-writer for having lost the correct reference. (If anyone finds it, please send the reference to me. Thanks.)

#########################################

# neighboring (not "overlapping") normal densities
dev.off()

x<-seq(-10,10,length=400)

y1<-dnorm(x) y2<-dnorm(x,m=3) par(mar=c(5,4,2,1)) plot(x, y2, xlim=c(-3,8), type="n", xlab=quote(Z==frac(mu[1]-mu[2], sigma/sqrt(n))), ylab="Density") polygon(c(1.96,1.96,x[240:400],10), c(0,dnorm(1.96,m=3),y2[240:400],0), col="grey80", lty=0)

lines(x, y2)

lines(x, y1)

polygon(c(-1.96,-1.96,x[161:1],-10), c(0,dnorm(-1.96,m=0), y1[161:1],0),

col="grey30", lty=0) polygon(c(1.96, 1.96, x[240:400], 10), c(0,dnorm(1.96,m=0), y1[240:400],0), col="grey30") legend(4.2, .4, fill=c("grey80","grey30"), legend=expression(P(abs(phantom(i)*Z*phantom(i))>1.96, H[1])==0.85, P(abs(phantom(i)*Z*phantom(i))>1.96,H[0])==0.05), bty="n")text(0, .2, quote(H[0]:~~mu[1]==mu[2]))

text(3, .2, quote(H[1]:~~mu[1]==mu[2]+delta))

#########################################

Charles Annis, P.E.

Charles.Annis@StatisticalEngineering.com
phone: 561-352-9699

eFax: 614-455-3265

http://www.StatisticalEngineering.com

-----Original Message-----

From: r-help-bounces@stat.math.ethz.ch

[mailto:r-help-bounces@stat.math.ethz.ch] On Behalf Of Isaac Barjis
Sent: Wednesday, September 27, 2006 11:08 AM
To: R-help@stat.math.ethz.ch

Subject: [R] t-stat Curve

Number of subjects = 25

Mean of Sample = 77

Standard Deviation (s) = 12

sem = 2.4

df = 24

The claim is that population mean is less than 80
* > 80

So our H0 (null hupotheis) is * > 80

> qt(.95,24)

[1] 1.710882

> qt(0.05, 24)

[1] -1.710882

tstat = -1.25 on t24 falls between 1.711 (.95,24) and *1.711 (.005,24)

How Could I sketch t curve for the above data where my * would be at the center?

Best Regards

Isaac

Dr. I. Barjis

Assistant Professor

Summer and Evening Coordinator

Department of Biological Sciences

Room P313

300 Jay Street

Brooklyn, NY 11201

Phone: (718)2605285

Fax: (718)2548680

Fax: (718) 254-8595 Department Office

http://websupport1.citytech.cuny.edu/Faculty/ibarjis

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. Received on Thu Sep 28 02:50:20 2006

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