From: Petr Pikal <petr.pikal_at_precheza.cz>

Date: Tue 13 Jul 2004 - 22:28:15 EST

R-help@stat.math.ethz.ch mailing list

https://www.stat.math.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html Received on Tue Jul 13 22:35:17 2004

Date: Tue 13 Jul 2004 - 22:28:15 EST

Hi

On 13 Jul 2004 at 12:28, luciana wrote:

> Dear Sirs,

*>
**> I am a R beginning user: by mean of R I would like to apply the
**> bootstrap to my data in order to test cost differences between
**> independent or paired samples of people affected by a certain
**> disease.
**>
**> My problem is that even if I am reading the book by Efron
**> (introduction to the bootstrap), looking at the examples in internet
**> and available in R, learning a lot of theoretical things on
**> bootstrap, I can't apply bootstrap with R to my data because of many
**> doubts and difficulties. This is the reason why I have decided to
**> ask the expert for help.
**>
**>
**>
**> I have a sample of diabetic people, matched (by age and sex) with a
**> control sample. The variable I would like to compare is their drug
**> and hospital monthly cost. The variable cost has a very far from
**> gaussian distribution, but I need any way to compare the mean
**> between the two group. So, in the specific case of a paired sample
**> t-test, I aim at testing if the difference of cost is close to 0.
**> What is the better way to follow for that?
**>
**>
**>
**> Another question is that sometimes I have missing data in my dataset
**> (for example I have the cost for a patients but not for a control).
**> If I introduce NA or a dot, R doesn't estimate the statistic I need
**> (for instance the mean). To overcome this problem I have replaced
**> the missing data with the mean computed with the remaining part of
**> data. Anyway, I think R can actually compute the mean even with the
**> presence of missing data. Is it right? What can I do?
*

your.statistic(your.data, na.rm=T)

e.g.

mean(your.data, na.rm=T)

or look at ?na.action e.g mean(na.omit(your.data))

Cheers

Petr Pikal

*>
**>
**>
*

> Thank you very much for your attention and, I hope, your help.

*>
**>
**>
**> Best wishes
**>
**>
**>
**> Luciana Scalone
**>
**> Center of Pharmacoeconomics
**>
**> University of Milan
**>
**> [[alternative HTML version deleted]]
**>
**> ______________________________________________
**> R-help@stat.math.ethz.ch mailing list
**> https://www.stat.math.ethz.ch/mailman/listinfo/r-help
**> PLEASE do read the posting guide!
**> http://www.R-project.org/posting-guide.html
*

Petr Pikal

petr.pikal@precheza.cz

R-help@stat.math.ethz.ch mailing list

https://www.stat.math.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html Received on Tue Jul 13 22:35:17 2004

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