# [R] greek in main title

Spencer Graves spencer.graves at pdf.com
Tue Jul 22 17:57:13 CEST 2003

```I was not able to get theta italicized, but I otherwise got something
matching my understanding of what you wanted.  Consider the following:

plotExpNormal <-
function (theta)
{
layout(matrix(c(1:4),2,2,byrow=TRUE))
par(bg = "cornsilk")
n <- c(1,10,25,50)
for(i in 1:4)  {
xbar <- rep(0, 1000)
for (j in 1:1000)
xbar[j] <- mean(rexp(n[i], rate = 1/theta))
heading <- substitute(exp(italic(theta)) == th, list(th=theta))
hist(xbar, prob = TRUE, breaks = "FD", main = title(heading,
font.main = 6),
col = "lightgray", xlab = expression(bar(x)))
xbar <- sort(xbar)
points(xbar, dnorm(xbar, mean = theta, sd = theta/sqrt(n[i])),
type = "l", col = 2)
}
}
plotExpNormal(2)
################
What do you think?
Spencer Graves
p.s.  I'm running R 1.7.1 under Windows 2000.

> Hello,
>
> I have written a function that demonstrates the CLT by
> generating samples following the exponential distribution,
> calculating the means, plotting the histogram, and drawing
> the limiting normal curve as an overlay.  I have the title
> of each histogram state the sample size and rate (1/theta)
> for the exponential (the output is actually 4 histograms),
> but I can't get the greek letter theta to appear in the
> heading.  Is this possible?  I can get nontext for the xlab
> and ylab pretty easily.
>
> Thanks, Jason
>
> Below is my code.  Currently it just writes out "theta."
>
> function (theta)
> {
>   layout(matrix(c(1:4),2,2,byrow=TRUE))
>   par(bg = "cornsilk")
>   n <- c(1,10,25,50)
>   for(i in 1:4)  {
>      xbar <- rep(0, 1000)
>      for (j in 1:1000)
>         xbar[j] <- mean(rexp(n[i], rate = 1/theta))
>      heading <- paste("Exp w/ theta =", theta, ", n = ", n[i])
>      hist(xbar, prob = TRUE, breaks = "FD", main = title(heading, font.main = 6),
>           col = "lightgray", xlab = expression(bar(x)))
>      xbar <- sort(xbar)
>      points(xbar, dnorm(xbar, mean = theta, sd = theta/sqrt(n[i])),
>         type = "l", col = 2)
>     }
> }
>
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```