
Probability and Statistics Basic Probability and Statistics Math Forum 
 LinkBack  Thread Tools  Display Modes 
September 26th, 2014, 06:44 AM  #1 
Member Joined: Aug 2014 From: scotland Posts: 45 Thanks: 0  Confused
University purchases particular type of elec components. 60% from company A 40 % from company B 2% from A are faulty 1% from B are faulty A) Draw tree diagram to represent the possible outcomes when a single component is selected at random. B) what is prob that this component was supplied by company A and faulty? C) calculate the prob that the component was defective? D) Given that the compnent was defective, what is the prob that it was supplied by A? Please help out. 
September 26th, 2014, 06:49 AM  #2 
Member Joined: Aug 2014 From: scotland Posts: 45 Thanks: 0 
i think tree diagram is ...............................^>98% not .......60%>Company A > 2% faulty 0 > .......40% > Compant B 1% faulty ..................................^>99% not If people can follow that haha 
September 26th, 2014, 07:07 AM  #3 
Member Joined: Aug 2014 From: scotland Posts: 45 Thanks: 0 
i/ What is the probability that this component came from company A and is defective? Probability supplied by A = 60% or 0.6 Probability defective if A = 2% or 0.02 Therefore; 0.6 x .02 = 0.012 So probability that this component came from company A = 0.6 (60%) and is defective = 0.012 (1.2%) ii/ Calculate the probability the component was defective I assume this incorporates both companies, so: Company A = 0.6 (60%) Company B = 0.4 (40% As per question i/ 0.6 x 0.02 = 0.012 (1.2%) Now for company B: 0.4 x 0.01 = 0.004 (0.4%) Now add probability the component picked was defective = 0.012 + 0.004 = 0.016 (1.6%) iii/ If was defective, what is probability it was supplied by company A? Probability component from company A AND defective = 0.012 / 0.016 = 0.75 = 75% probability component was from company A and is then ALSO defective 
September 26th, 2014, 07:13 AM  #4 
Math Team Joined: Dec 2013 From: Colombia Posts: 7,502 Thanks: 2511 Math Focus: Mainly analysis and algebra 
That's right. Perfect answer!
Last edited by v8archie; September 26th, 2014 at 07:15 AM. 
September 26th, 2014, 07:56 AM  #5 
Member Joined: Aug 2014 From: scotland Posts: 45 Thanks: 0  Thanks.
thank you..


Tags 
confused 
Thread Tools  
Display Modes  

Similar Threads  
Thread  Thread Starter  Forum  Replies  Last Post 
Confused  Shamieh  Calculus  3  September 7th, 2013 05:27 PM 
Confused with the Three  SarahW  Algebra  1  May 14th, 2013 01:50 PM 
So confused with this  charlieboon  Calculus  5  February 23rd, 2013 11:01 AM 
I am new and confused....  momoftwo  New Users  4  August 19th, 2009 07:15 PM 
So confused with this  charlieboon  Algebra  0  December 31st, 1969 04:00 PM 