Randomly Choose number from a matrix of several numbers?

Hello all, I will attempt to describe what I need help with the best I can.

    while response == 1 || response == 2 
      if response == 1
          N1=rand%number according to IGT (50% chance of being 0)
          N2=rand%number according to IGT
      totala= total - N1;
              fprintf(('You Lost:%.0f'),N1)
      totalb= total + N2;
              fprintf(('You Won:%.0f'),N2)
      elseif response == 1 && N == [10,20,30,40,50,60,70,80,90]
          N1=rand%number according to IGT + 10% increased chance of penalty (<50% chance of being 0)
          N2=rand%number according to IGT
          totala= total - N1;
              fprintf(('You Lost:%.0f'),N1)
          totalb= total + N2;
              fprintf(('You Won:%.0f'),N2)
      end

Where N1 and N2 will be a matrix (1xn) for example x=[50,50,0,0,250,350,450,500,500] I need the code to randomly select a number out of this matrix first, and if that works out, I would like to randomly select it to either be 0, or a number from that list. (if necessary, I can simply place 0's in the list)

This is essentially based off of the Iowa Gambling Task(IGT). As a person chooses a disadvantageous deck, they are penalized more over the long term than if one were to pick from the more advantageous decks. I don't feel comfortable sharing all of the program, but if needed, I'd be happy to send it via email for help.

Ignore the whole +10% increases, I plan on discussing this with my professor tomorrow and seeing if it is needed

Please feel free to ask for any other info Thanks,

Joe

Answer 1

[Sarah Wait Zaranek]

Instead of starting with your code - I will give an example of how I would do it. Hopefully this can see how you implement it in your large framework.

 x = rand(10,1); % some matrix you want to sample from
 idx = randi(length(x)) % random index into x
 randomval = x(idx);

 if randi(2)-1  % half the time assign to zero
   randomval = 0;
 end