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You are not logged in. #10726 20130505 07:07:48#10727 20130505 07:09:26
Re: Linear Interpolation FP1 FormulaI have lost the link to the STEP questions and I always come up to the TSR room on a google search. I am not getting 1 / 2 for iii. In mathematics, you don't understand things. You just get used to them. I have the result, but I do not yet know how to get it. All physicists, and a good many quite respectable mathematicians are contemptuous about proof. #10728 20130505 07:13:54
Re: Linear Interpolation FP1 FormulaI am getting 1/2 for that question... #10729 20130505 07:18:30
Re: Linear Interpolation FP1 FormulaHi; In mathematics, you don't understand things. You just get used to them. I have the result, but I do not yet know how to get it. All physicists, and a good many quite respectable mathematicians are contemptuous about proof. #10730 20130505 07:20:46
Re: Linear Interpolation FP1 FormulaI don't know what a multivariable hypergeometric distribution is... #10731 20130505 07:31:05
Re: Linear Interpolation FP1 FormulaThat is a good question. I am counting them all up by computer. The exact count of all permutations of 1,2,3,4,5,0,0,0,0,0,0 of length 4 is 501. The 501 can be verified with an exponential gf: Coefficient of x^4 is 167 / 8 when you times by 24 you get 501. 12 / 501 = 4 / 167 In mathematics, you don't understand things. You just get used to them. I have the result, but I do not yet know how to get it. All physicists, and a good many quite respectable mathematicians are contemptuous about proof. #10732 20130505 07:57:34
Re: Linear Interpolation FP1 FormulaI have been staring at your post for 20 minutes but I can't understand why your answer is different  unless your answer of 501 is wrong or something... I'm getting 1/2 with my method. #10733 20130505 08:01:33
Re: Linear Interpolation FP1 FormulaThe 501 is correct by ecxponential gf and by computer count. The 12 is correct because it is easy to do by hand and is just a mississippi problem. In mathematics, you don't understand things. You just get used to them. I have the result, but I do not yet know how to get it. All physicists, and a good many quite respectable mathematicians are contemptuous about proof. #10734 20130505 08:03:05
Re: Linear Interpolation FP1 FormulaYou mean 1 / 11 probability? #10735 20130505 08:27:33
Re: Linear Interpolation FP1 FormulaHi; In mathematics, you don't understand things. You just get used to them. I have the result, but I do not yet know how to get it. All physicists, and a good many quite respectable mathematicians are contemptuous about proof. #10736 20130505 19:36:26
Re: Linear Interpolation FP1 FormulaYes, those are the answers I got. How do you set up a hypergeometric distribution here? Would it save me time in a problem like this? #10737 20130505 19:41:25
Re: Linear Interpolation FP1 FormulaNo, the major difference between the kind of math I use and the kind you need to learn is big. In mathematics, you don't understand things. You just get used to them. I have the result, but I do not yet know how to get it. All physicists, and a good many quite respectable mathematicians are contemptuous about proof. #10738 20130505 19:48:10
Re: Linear Interpolation FP1 FormulaOkay, thanks. Unfortunately, for the remainder of this year, and probably the next 34 years, I must be a slave to the exam. #10739 20130505 19:53:53
Re: Linear Interpolation FP1 FormulaYes, the school system and industry do not appear to want to synchronize. School trains you one way and jobs train you for another. In mathematics, you don't understand things. You just get used to them. I have the result, but I do not yet know how to get it. All physicists, and a good many quite respectable mathematicians are contemptuous about proof. #10740 20130505 20:01:36
Re: Linear Interpolation FP1 FormulaWell, they have vocational courses, BTECs, apprenticeships, etc. over here which are replacements for GCSEs and Alevels, which are notoriously easier but also have a rather more applied perspective on things; a typical maths vocational course might be "Use of Mathematics" or a heavily financebased maths course. Unfortunately, Michael Gove, the moron that is the education secretary in England, is scrapping those and making things backward again. Thanks to our Conservative government, we could easily be about to witness Thatcher 2.0. #10741 20130505 20:11:41
Re: Linear Interpolation FP1 FormulaOver here they come out of the best universities, notoriously unable to solve a real world problem. They have to be totally retrained on the job.
This illustrates a hypergeometric distribution well; winners = 4, (the 4 numbered balls remaining) total= 4 + 6 ( total number of balls remaining ) trials = 3 ( you are picking 3 more balls ) num = 1 ( you need 1 more numbered ball ) I think I spoke too soon earlier. The hypergeometric might be difficult to remember but the multivariable version is easier to remember! Want to see it? In mathematics, you don't understand things. You just get used to them. I have the result, but I do not yet know how to get it. All physicists, and a good many quite respectable mathematicians are contemptuous about proof. #10742 20130506 06:35:42
Re: Linear Interpolation FP1 FormulaYes please  I was just thinking that it might be difficult to remember, I was trying to find similar problems to use it on today. How would you use the multivariable one here? #10743 20130506 06:45:18
Re: Linear Interpolation FP1 FormulaBest to illustrate with a clear example: In mathematics, you don't understand things. You just get used to them. I have the result, but I do not yet know how to get it. All physicists, and a good many quite respectable mathematicians are contemptuous about proof. #10744 20130506 06:49:50
Re: Linear Interpolation FP1 FormulaOh, I see. So for the STEP question, we have 5 numbered discs and 6 blank discs, so the probability of taking 4 numbered discs (without replacement) is #10745 20130506 06:55:02
Re: Linear Interpolation FP1 FormulaYes, that is correct. The multi one is easy to remember because of the obvious pattern. In mathematics, you don't understand things. You just get used to them. I have the result, but I do not yet know how to get it. All physicists, and a good many quite respectable mathematicians are contemptuous about proof. #10746 20130506 06:57:54
Re: Linear Interpolation FP1 FormulaThat looks useful to remember. I will write it in my notes... hopefully I'll get a chance to use it this exam season. #10747 20130506 07:03:43
Re: Linear Interpolation FP1 FormulaLots of problems can be thought of as urn problems and the hypergeometric is the distribution to use when there is no replacement. In mathematics, you don't understand things. You just get used to them. I have the result, but I do not yet know how to get it. All physicists, and a good many quite respectable mathematicians are contemptuous about proof. #10748 20130506 07:05:56
Re: Linear Interpolation FP1 FormulaI knew there must be a quicker way than just writing out all the probabilities... I always thought those 'without replacement' questions were extremely tedious because of that. Too bad they never teach us anything like this in school. #10749 20130506 07:21:45
Re: Linear Interpolation FP1 FormulaIt is the difference between school math and math ( I hate to say in the real world because it gets people very angry ). In mathematics, you don't understand things. You just get used to them. I have the result, but I do not yet know how to get it. All physicists, and a good many quite respectable mathematicians are contemptuous about proof. #10750 20130507 20:34:37
Re: Linear Interpolation FP1 FormulaI agree, it has always been a criticism of Alevels too  Michael Gove isn't really solving the problem though. Terence Tao wrote a problemsolving book with the same point in the foreword. 