December 18th, 2009, 08:03 PM  #1 
Newbie Joined: Dec 2009 Posts: 1 Thanks: 0  probabilities!
i'm a firsttime poster.. need some help on this one question i need to figure out to study for a final coming up ******** at a high school prom, the probability of exactly 15 out of 70 students that will wear allwhite attire (tuxedos, gowns, etc.) is about 0.2698. What is the probability of a randomly selected student that is wearing allwhite attire? ******** so for this question, do I use the formula: P= nCx (P^x) (q^nx) ? If yes, will the data i need to plug into it be: n = 70 x = 15 p = 0.2698 q = 0.7302 ? i'm asking this because the last part threw me off a bit  the probability of a randomly selected student wearing allwhite attire. what do I have to do to change my data points if I'm wrong? would n = 15 and x = 1 ??? 
December 18th, 2009, 10:03 PM  #2 
Senior Member Joined: Feb 2009 From: Adelaide, Australia Posts: 1,519 Thanks: 3  Re: probabilities! but I don't see any real solution. The maximum value of the lefthand side is 0.11552573 for p = 0.2142857. 
December 19th, 2009, 03:57 AM  #3 
Senior Member Joined: Dec 2009 From: Las Vegas Posts: 209 Thanks: 0  Re: probabilities!
Hi all; I am having the same problem : Has a maximum at 3 / 14 of .1155257 so their is no way any p can ever equal .2698. Are the numbers correct? 

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