January 15th, 2017, 09:43 AM  #1 
Newbie Joined: Jun 2016 From: New York Posts: 14 Thanks: 0 Math Focus: Calculus and Algebra  Statistical Multivariable Calculus
I am quierisome on a topic a doctor of math once opened my eyes to: applications of calculus to statistics. I am quite fond of both topics so I was attempting to find the area under a normal distribution. After some research, 8 found some clever ways using MultiVariable calculus to obtain some information and break the error function... however to no avail... I am not sure if I am doing something wrong because I don't understand how polar coordinates are converted or how to double integrate using those methods... My procedure is to assume the mean of the normal distribution and standard deviation are 0 and 1 respectively. To proceed, I integrated the normal distribution equation and walked into an issue. The error function... with some research I integrated it with respect to t for infinity to infinity. That worked fine so then I wanted to attempt other further adverterous means. I tried to find the area under a normal distribution use a Jacovian or whatever and I squared the integration, made theta and r substitution so I could integrate properly but the function does not add up to the cumulative probability it should in fact have of 42.1%. I decided that either my angle was wrong or my radius is wrong when I converted so I tried to figure out what pi/2x would give me 4.21 roughly and x is 6.4... but I'm not sure where pi/12.8 is coming from.... my radius may be off horribly instead. Any thoughts, knowledge or concerns? If anyone is concerned on how I made my calculations, an attached photo is administered this thread and some calculations were done using Mathematical by WolframAlpha. 
January 15th, 2017, 10:40 AM  #2 
Newbie Joined: Jun 2016 From: New York Posts: 14 Thanks: 0 Math Focus: Calculus and Algebra 
I realize I made a big error and accounted for it but still have a problem. The answer is not the correct one...


Tags 
calculus, multivariable, statistical 
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