[R] T.test error help

[Daniel Malter]

put another condition in your loop

if(all.equal(x,y)=TRUE) i=i+1 else t.test...

something in that direction.

best,
daniel 


-------------------------
cuncta stricte discussurus
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Von: r-help-bounces at r-project.org [mailto:r-help-bounces at r-project.org] Im
Auftrag von Amit Patel
Gesendet: Thursday, July 09, 2009 9:20 AM
An: r-help at r-project.org
Betreff: [R] T.test error help


Hi I am implementing the t.test in a loop and where the data is the same i
get an error message. 

Error in t.test.default(Samp3, Samp1, na.rm = TRUE, var.equal = FALSE,  : 
  data are essentially constant

The script i am using is 

for (i in 1:length(zz[,1])) {

Samp1 <- zz[i,2:17]
Samp2 <- zz[i,18:33]
Samp3 <- zz[i,34:47]
Samp4 <- zz[i,48:63] 

TTestResult[i,2] <- t.test(Samp2, Samp1, na.rm=TRUE, var.equal = FALSE,
paired=FALSE, conf.level=0.95)$p.value


TTestResult[i,3] <- t.test(Samp3, Samp1, na.rm=TRUE, var.equal = FALSE,
paired=FALSE, conf.level=0.95)$p.value

TTestResult[i,4] <- t.test(Samp4, Samp1, na.rm=TRUE, var.equal = FALSE,
paired=FALSE, conf.level=0.95)$p.value

}

Is there a way to make my loop ignore this problem and go onto the next
iteration





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