MathGroup Archive 2011

[Date Index] [Thread Index] [Author Index]

Search the Archive

Cumulative probability question

  • To: mathgroup at
  • Subject: [mg120583] Cumulative probability question
  • From: Peter Sisak <p-kun80 at>
  • Date: Sat, 30 Jul 2011 05:59:41 -0400 (EDT)
  • Delivered-to:

I have been experimenting with Mathematica in order to receive answers 
to my problem, so far without success. I have tried various forms of CDF 
and HypergeometricDistribution, but I seem to not know the proper 
addressing of the parameters for the problem.

The problem itself is the following (with numbers given for a more 
illustrative example): Given an urn containing N(=70) items in total, 
of which n(=4) are marked, we want to draw i(=2) or more marked 

a) What is the formula describing the number of draws required to 
succeed in drawing at least i items with a probability of at least 50%?
b) How do you make a graph of the probability (of drawing at least i 
items) graphed against the number of draws?
c) What are the equations that need to be solved to get a numerical 
answer on a) and b)?

Thank you for your assistance in advance
P=E9ter Sis=E1k

  • Prev by Date: Re: FinancialData errors
  • Next by Date: Re: Why won't this sum evaluate?
  • Previous by thread: Ctrl+Number Shortcuts doesn't work
  • Next by thread: Re: Cumulative probability question