how to show percentage of individuals for two groups on histogram?

Hi Ana,
This is a very common question about ggplot.
A quick search turns up lots of hits that answer your question. Here
are a couple
https://community.rstudio.com/t/trouble-scaling-y-axis-to-percentages-from-counts/42999
https://stackoverflow.com/questions/3695497/show-instead-of-counts-in-charts-of-categorical-variables

From reading those discussions, the following should work (untested)

ggplot(a, aes(x = HBA1C, fill=pheno)) + geom_histogram(aes(y =
stat(density)), binwidth = 0.5) +
      scale_y_continuous(labels = scales::percent_format())

HTH,
Eric


On Fri, May 22, 2020 at 7:18 AM Jim Lemon <drjimlemon at gmail.com> wrote:

Hi Ana,
Just noticed a typo from a hasty cut-paste. Two lines should read:

casehist<-table(cut(aafd$HBAIC[aafd$pheno=="case"],breaks=0:15))
controlhist<-table(cut(aafd$HBAIC[aafd$pheno=="control"],breaks=0:15))

Jim

On Fri, May 22, 2020 at 2:08 PM Jim Lemon <drjimlemon at gmail.com> wrote:

Hi Ana,
My apologies for the pedestrian graphics, but it may help.

# a bit of fake data
aafd<-data.frame(FID=paste0("fam",1000:2739),
 IID=paste0("G",1000,2739),FLASER=rep(1,1740),
 PLASER=c(rep(1,892),rep(2,848)),
 DIABDUR=sample(10:50,1740,TRUE),
 HBAIC=rnorm(1740,mean=7.45,sd=2),ESRD=rep(1,1740),
 pheno=c(rep("control",892),rep("case",848)))
par(mfrow=c(2,1))
casepct<-table(cut(aafd$HBAIC[aafd$pheno=="case"],breaks=0:15))
controlpct<-table(cut(aafd$HBAIC[aafd$pheno=="control"],breaks=0:15))
par(mar=c(0,4,1,2))
barpos=barplot(100*casehist,names.arg=names(casepct),col="orange",
 space=0,ylab="Percentage",xaxt="n",ylim=c(0,25))
text(mean(barpos),23,
 "Cases: n=848, nulls=26, median=7.3, mean=7.45, sd=1.96")
box()
par(mar=c(3,4,0,2))
barplot(100*controlhist,names.arg=names(controlpct),
 space=0,ylab="Percentage",col="orange",ylim=c(0,25))
text(mean(barpos),23,
 "Controls: n=892, nulls=7, median=7.3, mean=7.45, sd=1.12")
box()

Jim

On Fri, May 22, 2020 at 9:08 AM Ana Marija <sokovic.anamarija at gmail.com> wrote:

the result would basically look something like this on in attach or
the overlay of those two plots


On Thu, May 21, 2020 at 5:23 PM Ana Marija <sokovic.anamarija at gmail.com> wrote:

Hello,

I have a data frame like this:

head(a)

         FID   IID FLASER PLASER DIABDUR HBA1C ESRD   pheno
1 fam1000-03 G1000      1      1      38  10.2    1 control
2 fam1001-03 G1001      1      1      15   7.3    1 control
3 fam1003-03 G1003      1      2      17   7.0    1    case
4 fam1005-03 G1005      1      1      36   7.7    1 control
5 fam1009-03 G1009      1      1      23   7.6    1 control
6 fam1052-03 G1052      1      1      32   7.3    1 control

dim(a)

[1] 1698    8

I am doing histogram plot via:
ggplot(a, aes(x=HBA1C, fill=pheno)) + geom_histogram(binwidth=.5,
position="dodge")

there is 848 who have "case" in pheno column and 892 who have
"control" in pheno column.

I would like to have on y-axis shown percentage of individuals which
have either "case" or "control" in pheno instead of count.

Please advise,
Ana