Histogram with a normal curve

Produces a histogram for a vector of values and adds a normal curve with the same mean and standard deviation. The plot can be used to quickly compare the distribution of data to a normal distribution.

plotNormalHistogram(
  x,
  prob = FALSE,
  col = "gray",
  main = "",
  linecol = "blue",
  lwd = 2,
  length = 1000,
  ...
)

Arguments

x

A vector of values.

prob

If FALSE, then counts are displayed in the histogram. If TRUE, then the density is shown.

col

The color of the histogram bars.

main

The title displayed for the plot.

linecol

The color of the line in the plot.

lwd

The width of the line in the plot.

length

The number of points in the line in the plot.

...

Other arguments passed to hist.

Value

Produces a plot. Returns nothing.

Details

The function relies on the hist function. The normal curve has the same mean and standard deviation as the values in the vector.

Author

Salvatore Mangiafico, mangiafico@njaes.rutgers.edu

Examples

### Plot of residuals from a model fit with lm
data(Catbus)
model = lm(Steps ~ Gender + Teacher,
           data = Catbus)
 plotNormalHistogram(residuals(model))