Hey there! Sign in to join this conversationNew here? Join for free

s1 question 2016 juneeeeeee Watch

Announcements
    • Thread Starter
    Offline

    11
    ReputationRep:
    guys in part e why cant we just do 1/E(X)??????
    Attached Images
     
    • Thread Starter
    Offline

    11
    ReputationRep:
    also here in part f how come we add the probabiliuties and not multiply them!!!!!!!!
    Attached Images
     
    • Thread Starter
    Offline

    11
    ReputationRep:
    ?????????
    Offline

    7
    ReputationRep:
    (Original post by pondsteps)
    guys in part e why cant we just do 1/E(X)??????
    Hi i literally just did this question lol. So basically, for part e I just redrew the table but for Rebecca, have a go at that and it'll all make sense.


    Posted from TSR Mobile
    Offline

    7
    ReputationRep:
    Give me a minute i'll show u how i did it


    Posted from TSR Mobile
    Offline

    7
    ReputationRep:
    Name:  ImageUploadedByStudent Room1495228701.877726.jpg
Views: 15
Size:  133.8 KB

    The red arrows show u when Sarah's score is bigger then Rebecca's. So u just add those up. Do u understand now?


    Posted from TSR Mobile
    • Thread Starter
    Offline

    11
    ReputationRep:
    (Original post by b0bzzta)
    Name:  ImageUploadedByStudent Room1495228701.877726.jpg
Views: 15
Size:  133.8 KB

    The red arrows show u when Sarah's score is bigger then Rebecca's. So u just add those up. Do u understand now?


    Posted from TSR Mobile
    ohhh what u did makes sense but why doesnt the other way also work!!
    Offline

    7
    ReputationRep:
    (Original post by pondsteps)
    ohhh what u did makes sense but why doesnt the other way also work!!
    Just think about it for the first value. When you are calculating E(X) for sarah, you are going to do -2p. For Rebecca you are supposed to do (-1/2)*p=-p/2. Now instead of doing that, if you did 1/E(X), you would get -1/2p which is wrong. Does that help?


    Posted from TSR Mobile
 
 
 
  • See more of what you like on The Student Room

    You can personalise what you see on TSR. Tell us a little about yourself to get started.

  • Poll
    Should Spain allow Catalonia to declare independence?
    Useful resources

    Make your revision easier

    Maths

    Maths Forum posting guidelines

    Not sure where to post? Read the updated guidelines here

    Equations

    How to use LaTex

    Writing equations the easy way

    Student revising

    Study habits of A* students

    Top tips from students who have already aced their exams

    Study Planner

    Create your own Study Planner

    Never miss a deadline again

    Polling station sign

    Thinking about a maths degree?

    Chat with other maths applicants

    Can you help? Study help unanswered threads

    Groups associated with this forum:

    View associated groups
  • See more of what you like on The Student Room

    You can personalise what you see on TSR. Tell us a little about yourself to get started.

  • The Student Room, Get Revising and Marked by Teachers are trading names of The Student Room Group Ltd.

    Register Number: 04666380 (England and Wales), VAT No. 806 8067 22 Registered Office: International House, Queens Road, Brighton, BN1 3XE

    Quick reply
    Reputation gems: You get these gems as you gain rep from other members for making good contributions and giving helpful advice.