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Topic: Help with probability&stat problem
Replies: 47   Last Post: Jun 16, 2007 4:32 AM

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Jack Tomsky

Posts: 1,835
Registered: 12/18/04
Re: Help with probability&stat problem
Posted: Jun 12, 2007 9:27 AM
  Click to see the message monospaced in plain text Plain Text   Click to reply to this topic Reply

> My response
>
> I answered, strictly, what the OP asked: to use the
> normal approximation to evaluate a binomial problem,
> NOT what where the different procedures to do it, or
> what was the best one.
> The formula to find APPROXIMATELLY p(X<=a) is
>
> ______ z = (a + 0.5 - p*N) / s
> ______ s^2 = p * (1-p) * N
>
> and p(X<=a) = F(z) , the Normal Standard DF at the
> point z, X~ Binomial (p, N), p the constant
> probability of success at each Bernouilli N trials.
> This method is called currently the CLASSICAL
> CONTINUITY APPROXIMATION, a standard method that was
> indicated yet in this thread.
> Jack Tomsky did not take into account. HE DIDN`T PAY
> ATTENTION (!).
>
> Licas



The question did not ask for a normal approximation. It asked only for the probability. The professor would have liked my answer better than yours. Here is the original question.

"Past records show that at a given college 20% of the students who
began as psychology majors either changed their major or dropped out
the school. An incoming class has 110
beginning psychology majors. What is the probability that as many as
30 of these students leave the psychology program?"

Jack


Date Subject Author
6/11/07
Read Help with probability&stat problem
tutorny
6/11/07
Read Re: Help with probability&stat problem
briggs@encompasserve.org
6/11/07
Read Re: Help with probability&stat problem
tutorny
6/11/07
Read Re: Help with probability&stat problem
Randy Poe
6/11/07
Read Re: Help with probability&stat problem
tutorny
6/11/07
Read Re: Help with probability&stat problem
Bruce Weaver
6/11/07
Read Re: Help with probability&stat problem
tutorny
6/11/07
Read Re: Help with probability&stat problem
Bruce Weaver
6/11/07
Read Re: Help with probability&stat problem
C6L1V@shaw.ca
6/11/07
Read Re: Help with probability&stat problem
Randy Poe
6/11/07
Read Re: Help with probability&stat problem
tutorny
6/11/07
Read Re: Help with probability&stat problem
Nick
6/11/07
Read Re: Help with probability&stat problem
Jack Tomsky
6/11/07
Read Re: Help with probability&stat problem
Luis A. Afonso
6/11/07
Read Re: Help with probability&stat problem
Jack Tomsky
6/11/07
Read Re: Help with probability&stat problem
Luis A. Afonso
6/11/07
Read Re: Help with probability&stat problem
Jack Tomsky
6/12/07
Read Re: Help with probability&stat problem
Luis A. Afonso
6/12/07
Read Re: Help with probability&stat problem
Jack Tomsky
6/12/07
Read Re: Help with probability&stat problem
Luis A. Afonso
6/12/07
Read Re: Help with probability&stat problem
Jack Tomsky
6/12/07
Read Binomial law DF: a simple program
Luis A. Afonso
6/13/07
Read Re: Binomial law DF: a simple program
Jack Tomsky
6/13/07
Read Re: Help with probability&stat problem
Luis A. Afonso
6/13/07
Read Re: Help with probability&stat problem
Anon.
6/13/07
Read Re: Help with probability&stat problem
Jack Tomsky
6/13/07
Read Re: Help with probability&stat problem
Jack Tomsky
6/13/07
Read Re: Help with probability&stat problem
Luis A. Afonso
6/13/07
Read Re: Help with probability&stat problem
Jack Tomsky
6/13/07
Read Re: Help with probability&stat problem
Anon.
6/13/07
Read Re: Help with probability&stat problem
Luis A. Afonso
6/13/07
Read Re: Help with probability&stat problem
Jack Tomsky
6/13/07
Read Re: Help with probability&stat problem
Jack Tomsky
6/13/07
Read Re: Help with probability&stat problem
Anon.
6/13/07
Read FALSIFICATION
Luis A. Afonso
6/13/07
Read Re: FALSIFICATION
Jack Tomsky
6/13/07
Read Re: Help with probability&stat problem
Luis A. Afonso
6/13/07
Read Re: Help with probability&stat problem
Jack Tomsky
6/14/07
Read Re: Help with probability&stat problem
Luis A. Afonso
6/14/07
Read Re: Help with probability&stat problem
Luis A. Afonso
6/14/07
Read Re: Help with probability&stat problem
Jack Tomsky
6/14/07
Read Re: Help with probability&stat problem
Luis A. Afonso
6/15/07
Read Re: Help with probability&stat problem
Luis A. Afonso
6/15/07
Read Re: Help with probability&stat problem
Jack Tomsky
6/15/07
Read Re: Help with probability&stat problem
Luis A. Afonso
6/15/07
Read Re: Help with probability&stat problem
Jack Tomsky
6/15/07
Read Re: Help with probability&stat problem
Luis A. Afonso
6/16/07
Read Re: Help with probability&stat problem
Luis A. Afonso

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