siyna Posted February 21, 2009 Report Share Posted February 21, 2009 (edited) Hey guys! I'm kind of running late in completing my maths portfolio and trying to get it done as soon as possible. Our class has selected to do the “modelling probabilities in games of tennis problem. Although the problems seem pretty straightforward, I find myself stuck in a few problems in part two.This particularly concerns the part where I need to define the random variable Y (part 2). Initially I thought it was a binomial random variable Y with n=70 and p= 1808/2187, but it doesn't seem to work out. So, I'm guessing that I need to use stuff about binomial random variables to construct another random variable which models the situation. But this idea here entangles me even further into a problem that seems to have no ending. Could anyone help me a bit more with this, guiding me through the question?By the way, this is the problem I'm talking about.2. When Adam and Ben play against each other in club events, their probabilities of winning points are approximately the same as above. In club play, the tennis rules are generally followed (win with at least four points and by at least two points in each game), but to save court time, no game is allowed to go beyond 7 points. This means that if deuce is called (each player has 3 points), the next point determines the winner. Show that there are 70 possible ways that such a game might be played. To assist with this let Y be the number of points played. What values can Y take? For each possible value of Y find the number of possible ways that such a game could be played, and show the probability model for such a game. Be sure to define a random variable for the distribution.P.S. I've already found out the 70 ways that such a game may be played. It's the random variable Y I'm concerned about.Many thanks in advance! Edited February 21, 2009 by siyna Link to post Share on other sites More sharing options...
moneyfaery Posted February 21, 2009 Report Share Posted February 21, 2009 Well... if you were to plot out the distribution, what would you set as the x-axis variable? Link to post Share on other sites More sharing options...
siyna Posted February 21, 2009 Author Report Share Posted February 21, 2009 (edited) Well... if you were to plot out the distribution, what would you set as the x-axis variable?I would set the x-axis variable as the points that could be obtained in the non-extended play game between Adam and Ben: 4, 5, 6, 7.And the y-axis would be their corresponding probabilities. Edited February 21, 2009 by siyna Link to post Share on other sites More sharing options...
moneyfaery Posted February 21, 2009 Report Share Posted February 21, 2009 That's a possibility but there's another possibility. In non-extended play games, only two things change: the total number of points won and the number of points won by players. Link to post Share on other sites More sharing options...
siyna Posted February 21, 2009 Author Report Share Posted February 21, 2009 (edited) That's a possibility but there's another possibility. In non-extended play games, only two things change: the total number of points won and the number of points won by players.So the number of points won by each player would be 0, 1, 2, 3, 4 ?? Because you know, at 4 points the game is over...So the number of points won by each player would be 0, 1, 2, 3, 4 ?? Because you know, at 4 points the game is over...How is this supposed to help finding the random variable Y?Wait... I'm starting to see something. So I could integrate the points won by each player into the random variable Y? But then I would have to do this for each player apart, right? Edited February 22, 2009 by Aboo Link to post Share on other sites More sharing options...
moneyfaery Posted February 21, 2009 Report Share Posted February 21, 2009 Sorry, siyna. That's all the help I can give without making it too obvious. In fact, I've already made it too easy.Read through the other threads on this forum if you still need help:http://www.ibsurvival.com/forum/index.php?showtopic=4883http://www.ibsurvival.com/forum/index.php?showtopic=3676http://www.ibsurvival.com/forum/index.php?...ic=3878&hl= Link to post Share on other sites More sharing options...
siyna Posted February 22, 2009 Author Report Share Posted February 22, 2009 (edited) But am I on the right track or should I think about something else?I'm still confused. Thanks anyway; it gives me things to think about.It would be helpful if anyone else dropped a hint to help me find the way out. I would really appreciate that.I already sorted it out. Thanks for the help Edited February 24, 2009 by Aboo Link to post Share on other sites More sharing options...
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