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 October 6th, 2013, 12:14 PM #1 Newbie   Joined: Oct 2013 Posts: 18 Thanks: 0 simple probability Q Two coins are tossed. What is the conditional probability that two heads result given that there is a t least one head? let S be the sample space S = {{HH},{HT},{TH,{TT}} P(HH|HT,TH,HH) = P(HH n HT,TH,HH)/P(HT,TH,HH) = (1/4 * 3/4) / (3/4) = 1/4 is this correct? I'm finding it hard to determine what the question is actually asking October 6th, 2013, 05:21 PM   #2
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Re: simple probability Q

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 Originally Posted by lun123 Two coins are tossed. What is the conditional probability that two heads result given that there is a t least one head? let S be the sample space S = {{HH},{HT},{TH,{TT}} P(HH|HT,TH,HH) = P(HH n HT,TH,HH)/P(HT,TH,HH) = (1/4 * 3/4) / (3/4) = 1/4 is this correct? I'm finding it hard to determine what the question is actually asking
It is incorrect. HH is not independent of (HT,TH,HH).
The numerator should be P(HH) = 1/4, so the net result = 1/3. Tags probability, simple Thread Tools Show Printable Version Email this Page Display Modes Linear Mode Switch to Hybrid Mode Switch to Threaded Mode Similar Threads Thread Thread Starter Forum Replies Last Post ChidoriPOWAA Probability and Statistics 2 August 26th, 2013 03:02 PM maxgeo Probability and Statistics 1 April 23rd, 2013 09:37 AM forcesofodin Advanced Statistics 2 April 8th, 2010 11:36 AM Tyster Algebra 2 September 27th, 2009 04:48 PM mikeportnoy Advanced Statistics 2 September 27th, 2008 09:10 PM

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