Greek and Variables in Plot Titles

shadycats.r

shade.norm <- function(MU, SD, Lower, Upper, fill.color) {

cord.x <- c(Lower,seq(Lower,Upper,0.01),Upper)

cord.y <- c(0,dnorm(seq(Lower,Upper,0.01), 
mean = MU, sd = SD),0)

y.axis.text <-bquote("Density of N " * " " * "(" *
mu * " " * "=" * " " * .(MU) * ","* " " * sigma *
" " * "=" * " " * .(SD) * ")")

curve(dnorm(x, MU, SD), xlim=c(MU - 4*SD, MU +  4*SD),
 ylab=y.axis.text)

polygon(cord.x, cord.y, col=fill.color)
}
#The function is then called using shade.norm()
#So, which proportion of the population has IQs between 80 and 90?

shade.norm(100, 15, 80, 90, 'red')


#And, if we don't like red,

shade.norm(100, 15, 120, 130, 'blue')

#Or green?

shade.norm(5, 1.3, 2,4, 'green')

#Now, if we want to change how filled in the plot is, we can 
#add an additional argument to our function. To keep things 
#straight, I'm going to make a new function called
# shade.norm.density, and add a sixth argument, fill.density. 
#This then appears in the plotting command, as the argument
# that corresponds with, you guessed it, the density of the 
#color on the polygon function.

shade.norm.density <- function(MU, SD, Lower, Upper, 
fill.color, fill.density){

cord.x <- c(Lower,seq(Lower,Upper,0.01),Upper)

cord.y <- c(0,dnorm(seq(Lower,Upper,0.01), mean = MU, sd = SD),0)
y.axis.text <-bquote("Density of N " * " " * "(" *
mu * " " * "=" * " " * .(MU) * ","* " " * sigma *
" " * "=" * " " * .(SD) * ")")

curve(dnorm(x, MU, SD), xlim=c(MU - 4*SD, MU +  4*SD)
, ylab=y.axis.text)

polygon(cord.x, cord.y, col=fill.color, density = fill.density)
}
shade.norm.density(0, 1, 1, 2, 'darkblue', 45)