Anyone good at maths? (probability)
Home | Reviews and Features | Special Reports | Forums |

Results 1 to 7 of 7

Thread: Anyone good at maths? (probability)

  1. #1
    Join Date
    Feb 2004
    Posts
    373

    Anyone good at maths? (probability)

    Stuck with some basic maths probabilty.....

    Heres my question guys:
    [b]a component is made in 3 stages. the first stage involves building from one of four machines A,B,C and D all with equal probabilites. Second stage is trimmed using one machine either E,F or G, and finally polished using either machine H or J and it is twice as likely to be the former as H works faster[b]

    Determine the porbabilty of:
    1. a component is polished on machine H
    is it 2:1?

    2. it is trimmed on either machine F or G
    2/3 or 66%

    [b]3. a component is formed on either machine A or B, trimmed on F and polished on H]/b]
    i have no idea

    4. it is formed on machine A and polished on J
    ??

    5. formed on machine B and polished on machine H

    6. formed on machine A and trimmed on F
    A = 1/4 or 0.25, F = 1/3 or 0.3
    0.25 x 0.3 = 0.075
    0.25 + 0.3 - 0.075 = 0.475 or 47.5%
    is that right?


    any help on this guys would be a big help, show working out too?
    If you understood everything i said, you'd be me

    http://www.bridgesltd.co.uk
    Amber Integrated Controls & Automation

  2. #2
    Join Date
    Jan 2002
    Posts
    6,334
    i would probably fail whatever class those questions are from

  3. #3
    Join Date
    Feb 2002
    Posts
    3,265
    now its late, I am drunk and have no paper, still, I think its like this:


    1. is 2/3
    2. is 2/3
    3. is 1/9
    4. is 1/12
    5. is 1/6
    6. is 1/12

    Basically you set probabilty to each event on each stage separately.
    You have 3 stages and you always multiply in between. (if the probability of getting through certain stage is 1/4 and through another stage is 1/3, then MP it will give you 1/12)
    However when its "OR" on certain stage, you add the probabilities for all events "OR" includes.
    And when certain stage is left out the probabilty is of course 1, since it has to go via that stage anyway.

    hope that makes some sense
    Last edited by F_A_L_C_O_N; May 27th, 2005 at 08:06 PM.

  4. #4
    Join Date
    Dec 1999
    Location
    Bxl, Belgium
    Posts
    1,361

    Re: Anyone good at maths? (probability)

    Originally posted by adam1v
    A = 1/4 or 0.25, F = 1/3 or 0.3
    0.25 x 0.3 = 0.075
    0.25 + 0.3 - 0.075 = 0.475 or 47.5%
    is that right?


    any help on this guys would be a big help, show working out too?
    no.
    1/3=0.333333333
    also you multiply for "and" and add for "or", here you seem to do both. Why ?
    So as Falcon suggested, 1/4 x 1/3 = 1/12 = 0.083333 = 8.333%
    Looking intelligent takes more than looking coool.

  5. #5
    Join Date
    Feb 2004
    Posts
    373
    Originally posted by F_A_L_C_O_N
    now its late, I am drunk and have no paper, still, I think its like this:


    1. is 2/3
    2. is 2/3
    3. is 1/9
    4. is 1/12
    5. is 1/6
    6. is 1/12

    Basically you set probabilty to each event on each stage separately.
    You have 3 stages and you always multiply in between. (if the probability of getting through certain stage is 1/4 and through another stage is 1/3, then MP it will give you 1/12)
    However when its "OR" on certain stage, you add the probabilities for all events "OR" includes.
    And when certain stage is left out the probabilty is of course 1, since it has to go via that stage anyway.

    hope that makes some sense
    Thanks falcon, i have drawn a tree chart now and see how you have done it.
    makes great sense now, thanks mate.

    Adam
    If you understood everything i said, you'd be me

    http://www.bridgesltd.co.uk
    Amber Integrated Controls & Automation

  6. #6
    Join Date
    Feb 2005
    Location
    Oklahoma, USA
    Posts
    1,253
    LOL Are you coming on here to get homework help xD
    Intel 2500k @ 4.5 GHz | Sapphire 6870 1GB | 8GB DDR31600 | Gigabyte Z68A-D3H-B3 | 640 GB WD Caviar Black | 500GB WD something | ASUS Xonar DS | Logitech Z-5300e | Logitech G500 | Das Keyboard Cherry MX Brown | Dell S2740L

  7. #7
    Join Date
    Feb 2004
    Posts
    373
    Originally posted by ThePerson98
    LOL Are you coming on here to get homework help xD
    Yep, but now i understand better, and finish off the other 20 questions
    If you understood everything i said, you'd be me

    http://www.bridgesltd.co.uk
    Amber Integrated Controls & Automation

Thread Information

Users Browsing this Thread

There are currently 1 users browsing this thread. (0 members and 1 guests)

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •