# Plot histogram of variable with kernel density estimates and normal curve:

hist.kdnc = function(v,breaks=0,include.lowest=T,right=T,xlab=deparse(substitute(v)))
{
  xlab = xlab
  v = na.omit(v)
  x = v
  h = hist(v,plot=F)
  if (length(breaks)==1) breaks=h$breaks
  dens=density(v)
  ylim=range(0,h$density,dnorm(x=v,mean=mean(v),sd=sd(v)),dens$y)
  xlim=range(v,dens$x)
  hist(v,freq=F,breaks=breaks,include.lowest=include.lowest,right=right,
       xlim=xlim,ylim=ylim,col=grey(0.95),xlab=xlab,
       main=paste('Histogram of',xlab,'\nwith kernel density and normal curve '))
  lines(density(v),col='red')
  curve(dnorm(x,mean=mean(v),sd=sd(v)),col='blue',add=T)
}