Hey there! Sign in to join this conversationNew here? Join for free
    • Thread Starter
    Offline

    2
    ReputationRep:
    I feel really stupid for needing help on this question but oh well.

    http://www.ocr.org.uk/Images/65851-q...atistics-1.pdf

    On question number 4, I don't understand how to do part 2 and also part 4; I got the answer to part 4 correct, but I guessed it. Can someone explain to my why it's decrease, increase then stay the same for the other two please.

    For 4 part 2 I worked out that the median is 26th value so it's in the 31 to 35 class width but then I don't know what to do.
    Offline

    11
    ReputationRep:
    (Original post by Music99)
    I feel really stupid for needing help on this question but oh well.

    http://www.ocr.org.uk/Images/65851-q...atistics-1.pdf

    On question number 4, I don't understand how to do part 2 and also part 4; I got the answer to part 4 correct, but I guessed it. Can someone explain to my why it's decrease, increase then stay the same for the other two please.

    For 4 part 2 I worked out that the median is 26th value so it's in the 31 to 35 class width but then I don't know what to do.
    The midpoint of the class is 33. Is the median before, or after the middle value of the class. i.e. there are 28 values, is it before the median of the class 31 to 35.
    As for part iv)
    The mean is reduced as one of the values is reduced - look at how you calculate the mean, it should make sense.
    The sd increases because the lead time gets further away from the mean - the spread increases (this effect is greater than the effect of the reduced mean)
    The person who came first changing does not affect the median - they are still first.
    The IQR is unaffected as well as the person who came first does not lie between Q1 and Q3.
 
 
 
  • 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
    Brexit voters: Do you stand by your vote?
    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

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