Tables extraction in R ?
On 07/07/2012 03:23 AM, Greeknovice wrote:
Hi, I 'm a novice user of R statistics and my hands-on experience with it is minimal. I want to create a table for my MBA course assignment that looks like the ones that SPSS and MS Excel produces ,the data that the table has to include are the following :
table(agec)
agec 1 2 3 749 160 32
x=table(agec) x
agec 1 2 3 749 160 32
prop.table(x)
agec
1 2 3
0.79596174 0.17003188 0.03400638
prop.test(749,941)
1-sample proportions test with continuity correction
data: 749 out of 941, null probability 0.5
X-squared = 328.5186, df = 1, p-value< 2.2e-16
alternative hypothesis: true p is not equal to 0.5
95 percent confidence interval:
0.7684801 0.8209873
sample estimates:
p
0.7959617
prop.test(160,941)
1-sample proportions test with continuity correction
data: 160 out of 941, null probability 0.5
X-squared = 408.5016, df = 1, p-value< 2.2e-16
alternative hypothesis: true p is not equal to 0.5
95 percent confidence interval:
0.1468831 0.1959230
sample estimates:
p
0.1700319
prop.test(32,941)
1-sample proportions test with continuity correction
data: 32 out of 941, null probability 0.5
X-squared = 815.4899, df = 1, p-value< 2.2e-16
alternative hypothesis: true p is not equal to 0.5
95 percent confidence interval:
0.02374674 0.04822644
sample estimates:
p
0.03400638
This "percentages and confidence intrevals" table should be in an image
file format since I have to upload it to a wiki page.
Is there a specific command or even a series of commands I can use in order
to extract this "graphics" table automatically, or I have to create it
manually using Excel for example?
Hi Greeknovice,
Combining results from different functions into a specified format is a
common problem in R. As you noted, it has to look like some default
format used in another system. The flexibility of R allows you to do
this, but you have to write a function or two like this:
table_with_prop_test<-function(x) {
counts<-table(x)
ncounts<-length(counts)
totalx<-sum(counts)
pcts<-round(100*counts/totalx,1)
X2<-df<-p<-lcl<-ucl<-rep(0,ncounts)
for(i in 1:ncounts) {
proptest<-prop.test(counts[i],totalx)
X2[i]<-round(proptest$statistic,2)
df[i]<-proptest$parameter
p[i]<-round(proptest$p.value,3)
lcl[i]<-round(proptest$conf.int[1],3)
ucl[i]<-round(proptest$conf.int[2],3)
}
tptmat<-cbind(counts,pcts,X2,df,p,lcl,ucl)
return(tptmat)
}
Then if you want to turn the result into an image, you can do something
like this:
library(plotrix)
png("table_with_prop_test.png",height=200)
plot(1:5,type="n",axes=FALSE,xlab="",ylab="")
addtable2plot(1,3,table_with_prop_test(x),
display.rownames=TRUE)
dev.off()
Jim