How can I overlay a density plot (normal curve) over a histogram?
Article ID: KB0080747
Updated On:
| Products | Versions |
|---|---|
| Spotfire S+ | All supported versions |
Description
User looking for S+ code to overlay a density plot (normal curve) over a histogram.
Issue/Introduction
How can I overlay a density plot (normal curve) over a histogram?
Environment
Product: TIBCO Spotfire S+
Version: All supported versions
OS: All supported operating systems
--------------------
Resolution
Here is one approach to combining the density (normal curve) and the histogram. The key here is the probability=TRUE argument to hist(), which puts it on a 0-1 vertical scale rather than a scale of bin counts. Then, computing the interquartile range is a fairly reasonable way to set the horizontal scale of the density function.
x <- rnorm(500)
hist(x, prob=T)
iqd <- summary(x)[5] - summary(x)[2]
lines(density(x, width=2*iqd))
References:
You can view the help files on any of the functions used in the code above by typing a question mark followed by the function name at your S+ command prompt. For example:
> ?hist
> ?density
x <- rnorm(500)
hist(x, prob=T)
iqd <- summary(x)[5] - summary(x)[2]
lines(density(x, width=2*iqd))
References:
You can view the help files on any of the functions used in the code above by typing a question mark followed by the function name at your S+ command prompt. For example:
> ?hist
> ?density
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