R help - Feb 2012 - Error while doing T-test

hi,

i am using R for first time. i am trying to do T-test for a sample set with
three variables. i attached my data set as CSV file.
but when i do "t.test(data$Day.1,data$Day.2,var.equal=T)" i get this
following error. Can anyone please help e identify the problem.

Error in if (stderr < 10 * .Machine$double.eps * abs(mx)) stop("data are
essentially constant") :
  missing value where TRUE/FALSE needed
In addition: Warning message:
In mean.default(x) : argument is not numeric or logical: returning NA

Thanking you in advance.
Deepak

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Hi
> 
> hi,
> 
> i am using R for first time. i am trying to do T-test for a sample set 
with
> three variables. i attached my data set as CSV file.
> but when i do "t.test(data$Day.1,data$Day.2,var.equal=T)" i get
this
> following error. Can anyone please help e identify the problem.
> 
> Error in if (stderr < 10 * .Machine$double.eps * abs(mx))
stop("data are
> essentially constant") :
>   missing value where TRUE/FALSE needed
> In addition: Warning message:
> In mean.default(x) : argument is not numeric or logical: returning NA
I think than in this case the error message is self explaining.
> In mean.default(x) : argument is not numeric or logical: returning NA
data$Day.1

is not numeric or logical so it is probably character or date.

look at str(data)

Regards
Petr

> 
> Thanking you in advance.
> Deepak
> 
>    [[alternative HTML version deleted]]
> 
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