'draw.normal' computes the X-Y coordinates for a normal probability density function.  It either plots the function or simply outputs the coordinates.

ARGUMENTS: 

'mn' = population mean

'sd' = population standard deviation.

'xlimit=NA' permits user control of the x axis limits.

'ylimit=NA' permits user control of the y axis limits.

'show.axes = FALSE' (default) omits axes. 

'plot.dist = TRUE':  If FALSE, then no plot is made and the X-Y coordinates for the graph are outputted.  If TRUE, a plot is made and the coordinates are not outputted.

'cdf = FALSE':  If FALSE, the plot displays a density function and the Y coordinates are the height of the density function.  If TRUE, the plot displays a cumulative distribution function and the Y coordinates are the height of the cumulative distribution function.  

`Label = 'default'`:  The default setting creates a graph title that states the parameters of the gamma distribution.  The label can be set to other values if preferred.

'Lwd' controls the line weight on the graph.

'cred.int' & 'plot.cred.int' control whether or not a credible interval is plotted and the probability level of the credible interval.

'cred.lab' controls whether or not the probability level of the credible interval is plotted inside of the density plot.

'cred.col' controls the color of the area under the credible interval.

'draw.phi' plots the density function on the [0, 1] interval that corresponds to the phi transformation of a given normal distribution.  For example, if we specify a normal distribution with mu = 4, and sd = 9, then 'draw.phi' plots the probability density that is implied if we apply the phi transformation to the random variables that are drawn from this distribution.  The phi transformation computes cumulative normal probability for the standard normal distribution (mean = 0, sd = 1).  Thus 'draw.phi' is a uniform distribution when we specify mu = 0 and sd = 1, but if we specify, e.g., mu = 4, sd = 16, then the phi transformation of this distribution is peaked below 0.50 and has a roughly normal distribution.

ARGUMENTS

'mu' - mean of the normal distribution

'sd' - standard deviation of the normal distribution

'xlimit = c(0, 1)' - range on the X axis of the probabilities that are plotted.  

'ylimit = NA ' - range on the Y axis of the density plot

'plot.dist = TRUE' (default) - Should the density be plotted?  If 'plot.dist = FALSE', the density is not plotted and the coordinates for the density plot are outputted as a 999 x 2 matrix.

'Label = 'default'' - Specify a label for the graph, or accept the default label.

'Lwd = 2' - Line width on the density plot.  

'show.axes = FALSE' (default) - if TRUE, the Y axis is displayed.