Undefined function 'exprnd' for input arguments of type 'double'

I am trying to call this function from a script but when I run it I get the error: Undefined function 'exprnd' for input arguments of type 'double' I am using psychtoolbox and stat toolbox.

function y = expsample(mean_t,min_t,max_t,interval)
% produce a random sample from an exponential distribution (with
% given mean) within limits (min/max) given a mean. round to nearest interval
% this is useful for generating jittered time intervals between
% stim presentations for event-related designs

tmp=exprnd(mean_t);
tmp=tmp-mod(tmp,interval); % round to nearest interval
while (tmp < min_t | tmp > max_t),
   tmp=exprnd(mean_t);
   tmp=tmp-mod(tmp,interval); % round to nearest interval   
end;
y=tmp;

Answer 1

[Star Strider]

If you have successfully used the Statistics Toolbox before this, you need to be certain that the exprnd function still exists on your MATLAB path, and that it is not being ‘shadowed’ (or ‘overshadowed’) by another function.

Type this in your script or the Command Window:

which exprnd -all

On my Windows machine, I get only one result:

C:\Program Files\MATLAB\R2015a\toolbox\stats\stats\exprnd.m

If you get more than one result, you need to rename the function that is not in the Statistics Toolbox. Otherwise, you may need to reset the toolbox cache. Type these in your script or the Command Window:

restoredefaultpath 
rehash toolboxcache

If none of these work, contact MathWorks Support.

[Britta Hahn]

When I did that, a comment came up beside and said " Has no license available"

[Star Strider]

You need to contact either your MATLAB license administrator to get the Statistics Toolbox, or MathWorks Support, depending on your situation.