[R] Odp: Write function multiple tests and write summary table

[Petr PIKAL]

Petr Pikal
petr.pikal at precheza.cz
724008364, 581252140, 581252257


r-help-bounces at r-project.org napsal dne 27.05.2008 10:52:18:

> Dear R community,
> 
> I am not experienced in writing functions and need your help to 
understand
> the strategy to face the following problem:
> 
> I have a group of independent numerical variables, let's say
> 
> a<-c(1,3,2,6,9,2,2,3,4,1)
> b<-c(2,3,3,4,5,6,2,1,1,6)
> c<-c(0,2,4,4,7,6,7,1,2,2)
> d<-c(0,0,0,1,0,2,1,3,1,2)
> e<-c(9,2,3,1,1,1,0,2,5,6)
> 
> and a grouping variable,
> 
> group<-c
> 
("case","case","case",","case",","case","control","control","control","control","control")
> 
> I want to apply a test for every variable independently and store the
> summary result in a table
> 
> for example
> 
> mod1<-aov(a~group)
> mod2<-aov(b~group)
> .
> .
> .
>  generate summary table
> 
> 
> Any suggestions?

Use lists.

lll<-list(a,b,c,d,e)
group<-factor(group)
lapply(lll, function(x) summary(aov(x~group)))
[[1]]
            Df Sum Sq Mean Sq F value Pr(>F)
group        1    8.1     8.1    1.35 0.2788
Residuals    8   48.0     6.0 

[[2]]
            Df Sum Sq Mean Sq F value Pr(>F)
group        1    0.1     0.1   0.025 0.8783
Residuals    8   32.0     4.0 

[[3]]
            Df Sum Sq Mean Sq F value Pr(>F)
group        1   0.10    0.10  0.0142 0.9081
Residuals    8  56.40    7.05 

[[4]]
            Df Sum Sq Mean Sq F value   Pr(>F) 
group        1   6.40    6.40  14.222 0.005456 **
Residuals    8   3.60    0.45 
---
Signif. codes:  0 ‘***’ 0.001 ‘**’ 0.01 ‘*’ 0.05 ‘.’ 0.1 ‘ ’ 1 

Further improvement will be necessary because it is not clear what the 
output shall look like.

Regards.

Petr

 
> Thank you
> 
> Fabio
> 
> 
> 
> -- 
> Fabio Sánchez, MD, MSc, PhD
> Unit of Dermatology and Venereology
> Department of Medicine
> Karolinska Institute
> SE-17176 Karolinska University Hospital
> Phone: +46 8 51772158
> Fax: +46 8 51773620
> 
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