Hey there! Sign in to join this conversationNew here? Join for free
x Turn on thread page Beta
    • Thread Starter
    Offline

    10
    ReputationRep:
    how do you interpret contribution tables for chi squared ocr mei s2?
    • Very Important Poster
    Online

    21
    ReputationRep:
    Very Important Poster
    (Original post by esmeralda123)
    how do you interpret contribution tables for chi squared ocr mei s2?
    I have googled this but found nothing - do you have a link or image?
    • Thread Starter
    Offline

    10
    ReputationRep:
    (Original post by Kevin De Bruyne)
    I have googled this but found nothing - do you have a link or image?
    for example, how would you answer this question, i have looked at the mark scheme but don't understand what tables to use:
    question 4 http://mei.org.uk/files/papers/2012_Jan_s2.pdf
    mark scheme attached too
    Offline

    12
    ReputationRep:
    You don't use the tables you use equations.

    To get 9.3180, you do (column total x row total)/ total observed. So (98 x 29)/305

    And for 6.3332, its (observed-expected frequences)^2/expected frequency. So (17-9.3180)^2/9.3180


    Is this what you were confused about or something else?
    • Thread Starter
    Offline

    10
    ReputationRep:
    (Original post by AzureCeleste)
    You don't use the tables you use equations.

    To get 9.3180, you do (column total x row total)/ total observed. So (98 x 29)/305

    And for 6.3332, its (observed-expected frequences)^2/expected frequency. So (17-9.3180)^2/9.3180
    i know but the written part of the question is what i don't understand:
    Q4iv)
    Offline

    12
    ReputationRep:
    (Original post by esmeralda123)
    i know but the written part of the question is what i don't understand:
    Q4iv)
    The larger the value is, the more unexpected the value is.(i.e. it's not the frequency expected). So looking at Woodland finches, there are 10 seen, and approx 10 expected. The overall statistic is 0 as it's what you expect. However with garden thrushes you see 74, however you only expect to see 31ish and as such the contribution to the overall statistic is much greater.
    Does that sort of help and make sense?
    Offline

    15
    ReputationRep:
    Aw MEI S2 .. cute.
 
 
 
Reply
Submit reply
Turn on thread page Beta
Updated: March 11, 2018
Poll
Do you agree with the proposed ban on plastic straws and cotton buds?
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

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.