Re: A problem with solving some nonlinear system

*To*: mathgroup at smc.vnet.net*Subject*: [mg87300] Re: A problem with solving some nonlinear system*From*: Jens-Peer Kuska <kuska at informatik.uni-leipzig.de>*Date*: Mon, 7 Apr 2008 05:15:56 -0400 (EDT)*References*: <fta9n1$eav$1@smc.vnet.net>

Hi, we all like to do the home work of students! NSolve[{Integrate[ PDF[NormalDistribution[0, 1], z], {z, (c - 75)/10/Sqrt[n], Infinity}] == 5/100, Integrate[ PDF[NormalDistribution[0, 1], z], {z, (c - 78)/10/Sqrt[n], Infinity}] == 9/10 }, {c, n}] ?? Next time, make your home work *alone* because otherwise you will learn nothing. Regards Jens Walkman wrote: > Hi. This is the first posting in this board(in Englsigh?). So, if > there is any punctuation error or misunderstood, please let me know. > > The problem itself is in the book 428p. "Introduction to Mathematical > Statistics 6E" > > In solving this problem, I've got stuck with this practical problem. > > To find n and c such that > > Integrate[f,{z,(c-75)/10/sqrt(n),inf}] = .05 > Integrate[f,{z,(c-78)/10/sqrt(n),inf}] = .9 > > where f = N(0,1); N -> Normal Distribution of which mean = 0 and > variance = 1 > > How can I solve this problem in mathematica? or any math-computational > program? (e.g. R) >