Ti-83 Programming Question

[JbAngleSlam]

I am having major issues with a simulation program for my TI-83. here is the question:

a pair of dice is rolled repeatedly. simulate the probability that a sum of 7 is rolled before a sum of 8.

i know the answer is 6/11 but i cant get the program right on my calc.

any help would be great

thanks

[CompWiz]

could you give some more details? Source code?

Kerm's SourceCoder is an easy way to post your source code. Just upload the file, and it'll take care of the rest.

[JbAngleSlam]

Im not really sure what you mean by source code. I have to come up with a programming code for my graph calc that will simulate this probability.

I cant figure it out.

[anykey]

Looks like we need to clear up some terminology first...
Source code = programming code

[thegamefreak0134]

If you need the logic for such a thing, it's really very simple. You create a list from 1 to 11, and then every roll of the dice adds 1 to L1(number - 1), because the dice rolls start at 2.

To dislplay the rolls right, you will need somewhere in the range of a few thousand rolls of the dice, so keep that in mind. Then you should make a graph onscreen of the ratios between numbers. This can be done by setting xmin and xmax to your spacing preference, then setting ymin to 0 and ymax to the highest value in the list. (use the max() function) then just draw lines to represent the current graph, and after a while the trend should start to appear as a "hill" with the peak of the hill being right on 7.

This kind of probability simulation is already implemented in an APP on most TI-83 Plus family calcs, called ProbSim I believe.

Good lick with your program!

-gamefreak

[King Harold]

there is a formula for it aswell, but i'd have to look in my math book of 2 years ago (I will if you don't find a solution though)

[silver calc]

Just because ideally the probability is 6/11 doesn't mean that experimentally you will get that. How many trials did you use?