Making a Conditional Probability ChartDate: 05/17/2000 at 14:44:08 From: Melisss Dolan Subject: Probability I have asked many math teachers to help me with this problem, and they can't figure it out, so I turn to you. Medical records show that in a group of patients screened for lung cancer, 10% have the disease. Of those who have lung cancer, 93% are smokers. Of those who do not have lung cancer, 28% are smokers. If a person selected from this group is a smoker, what is the probability that the person has lung cancer? Date: 05/18/2000 at 09:05:19 From: Doctor Anthony Subject: Re: Probability Making a chart: |Lung cancer No lung cancer | Total ---------|------------------------------|------- Smoker |0.1 x 0.93 0.9 x 0.28 | 0.345 Non-Smoker|0.1 x 0.07 0.9 x 0.72 | 0.655 ---------|------------------------------|-------- Total | 0.1 0.9 | 1.00 Given that a person is a smoker, the probability he has cancer 0.1 x 0.93 = ---------- = 0.26956 0.345 - Doctor Anthony, The Math Forum http://mathforum.org/dr.math/ |
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