boxplotPerc

Allows user to specify the percentile values of boxplot whiskers while still using the standard MATLAB boxplot syntax & options.

PURPOSE: A boxplot function which allows users to specify the percentile
values of boxplot whiskers while still using the standard MATLAB boxplot options.

INPUTS: Use syntax exactly as with the standard "boxplot" command, but
with a scalar or vector of percentile values as the second input.

data - a data matrix as with normal boxplot

percentile - a vector of 2 percentile values [lower, upper],
specified as percentages --OR-- a single scalar indicating the
desired span of percentiles. If the scalar is used, the program
solves for the necessary [lower, upper] values.
Examples: [5 95] or equivalently [90]
[2.5 97.5] or equivalently [95];

varargin - all the remaining boxplot options, according to the
typical MATLAB syntax.

OUTPUT: a boxplot with the whiskers set to the specified percentile or
percentile range values.

EXAMPLE: Here is a highly asymmetric data set along with a call to the boxplotPerc function:

data = normrnd(-1,1,100,5).^3;
boxplotPerc(data,90, 'notch','on','symbol','o','Widths',[0.1:0.1:0.5])

NOTE: This code was inspired by "Box Plot with Whiskers Plotted at Fixed Percentiles" by Robert:
https://www.mathworks.com/matlabcentral/fileexchange/22526-box-plot-with-whiskers-plotted-at-fixed-percentiles