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bobbym
2013-04-06 01:22:39

Might be better to post it in a new thread.

Agnishom
2013-04-06 01:16:36

May I post another problem of Bayes' theorem?

bobbym
2013-04-05 22:10:23

Hi gAr;

Thanks for the pdf.

gAr
2013-04-05 20:17:50

You're welcome!
Found a pdf which solved for the expected number of steps for the rat to exit from the maze : http://www.columbia.edu/~ks20/stochasti … -I-MCI.pdf

bobbym
2013-04-05 19:57:57

Hi gAr;

Thanks for providing that!

gAr
2013-04-05 19:51:52

Hi,

I derived the probabilities for (iii) from the matrix
st                1                2                3          end1        end23
st         0 0.7000000 0.2000000 0.1000000 0.0000000 0.0000000
1          0 0.0000000 0.5000000 0.0000000 0.5000000 0.0000000
2          0 0.3333333 0.0000000 0.3333333 0.3333333 0.0000000
3          0 0.0000000 0.3333333 0.0000000 0.0000000 0.6666667
end1    0 0.0000000 0.0000000 0.0000000 1.0000000 0.0000000
end23  0 0.0000000 0.0000000 0.0000000 0.0000000 1.0000000

and used bayes' rule

1_s means starts at first room, 1_e means exits from first room

You need to slightly change the matrix for P(1_e|1_s) by changing .7 to 1 and rest in that row to zeroes.

bobbym
2013-04-05 18:55:20

I am having trouble getting the exact answer though. How did you get it?

gAr
2013-04-05 18:45:34

Hi bobbym,

Thanks for confirming.

bobbym
2013-04-05 18:25:18

Hi;

That is what I am getting too.

gAr
2013-04-05 16:51:25

Hi,

The simulations match closely with the answers for (ii) and (iii), so I believe they are right.

bobbym
2013-04-05 05:58:36

Hi gAr;

Yes, it did but the trouble was with the denominator I chose. anonimnystefy used bayes theorem to choose the right one.

gAr
2013-04-05 05:00:25

Hi,

And got 56 / 63 for (iii)
Conditional probability is posing a problem to simulate, hmmm!

Okay, eat well. I may go to sleep in a while, see you "tomorrow".

bobbym
2013-04-05 04:55:59

Hi gAr;

I am going to eat, I am starving. Will see you in a bit.

gAr
2013-04-05 04:54:18

Okay, verify when you are done.

bobbym
2013-04-05 04:47:14

We stopped at i) I think I was getting tired.