Probabilities in matlab

**Brunoz** · 05-01-2010

Hello,
As part of a project I have a problem, It performs a series of throws of a dice and it stops when it gets an ace. Then there are the number of shots needed. I try to do a simulation in matlab and I can not make a program that would allow me to get results (if there was a loop while I'd finish but it is not). In short which are the probabilities in metlab to use for my project. If you have an idea that would help me. Thank you in advance.

**Brunoz** · 05-01-2010

Hello
Well I can not get my while loop. The probability of getting an ace during a run is 0.167.
So I make 100 simulations:

Code:

a = 1

Choose u between 0 and 1

Code:

As u > 0.167

fair: a = 1 and u choose between 0 and 1.
This will gives me a.

**kelfro** · 05-01-2010

Hello
I'd rather run a simulation of the die-

Code:

in = rd (5 * rand (1)) + 1;
start = 1;
while (from ~ = 6)
    in = rd (5 * rand (1)) + 1;
    start = start + 1;
end

2 comments:
- don 't forget to initialize the pseudo random generator, "help rand" should tell you how.
- law distribution that you want, you can use randp, randn, randg

**Brunoz** · 05-01-2010

Hello
Thank you for the code. But before your answer I tried to search a bit by the following code:

Code:

for i = 1:100;
a (1, i) = 1;
u (1, i) = rand;
while u (1, i)> 0.1667
a (1, i) = a (1, i) +1;
u (1, i) = rand;
end
end
stem (a), grid
mean (a),% average

Matlab gives me as error message: "Missing operator, comma, or semi-colon."
I do not understand what is wrong. Thank you in advance.

**Modifier** · 05-01-2010

Hello everyone,
I have a big foot to ask in relation to a problem that I can not solve.
Would there be someone who could help me build a mathematical model using two data vectors using scilab. Thank you. Help please.

**kelfro** · 05-01-2010

Hello
I advise you describe what you want to do what you have done and what you can not make because

construct a mathematical model using two data vectors

This does not mean much.
In me your script work, but it's true that I use OCTAVE which may be different behavior of MATLAB. Perhaps the ";" on line "for" problem? Or perhaps that MATLAB requires an argument "rand"?