Generate catch trial numbers in blocks of a certain length

Hi,

I am doing an experiment and I want to insert a certain amount of catch trials randomly during my experiment. It is important that these catch trials are more or less equally spaced troughout the experiment. Right now I solved it in the following way:

%% A function to randomly create the intances of the catch trials

% By Bram van Adrichem

clear all

close all

clc

NrTrials = 150;

NrEC = 15;

NrCatchTrials = 15;

NrData = NrTrials/NrEC;

BlockStart = 2;

RandomNumber = CatchTrialMoment(NrTrials,NrCatchTrials,BlockStart);

function RandomNumber = CatchTrialMoment(NrTrials,NrCatchTrials,BlockStart)

BlockLength = NrTrials/NrCatchTrials;

for ii = 1:NrCatchTrials

RandomNumber(ii) = (BlockLength*(ii-1)) + datasample(BlockStart:BlockLength,1);

end

end

I think this code works, but my two question are:

Is there already a matlab function that can do this?

Are there more people struggling with this kind of problem, because then I could upload it to the file- exchange