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

    0
    ReputationRep:
    When you're doing a two tailed test i.e. h1: p cannot equal 0.5 do you find P(X<x) or P(X>x) or is either fine? My book says if either of them is less than a (significance level) then reject the null hypothesis, is that correct?
    • Thread Starter
    Offline

    0
    ReputationRep:
    Zacken
    Offline

    22
    ReputationRep:
    (Original post by mp_x)
    When you're doing a two tailed test i.e. h1: p cannot equal 0.5 do you find P(X<x) or P(X>x) or is either fine? My book says if either of them is less than a (significance level) then reject the null hypothesis, is that correct?
    If your significance level is n\% then you need to find P(X \leq x) \leq \frac{n}{2} \% and P(X \geq x) \leq \frac{n}{2} \% (equality signs need to be adjusted for discrete stuff)

    This is a really good video explaining two tailed tests: http://www.examsolutions.net/maths-r.../example-5.php
    • Thread Starter
    Offline

    0
    ReputationRep:
    (Original post by Zacken)
    If your significance level is n\% then you need to find P(X \leq x) \leq \frac{n}{2} \% and P(X \geq x) \leq \frac{n}{2} \% (equality signs need to be adjusted for discrete stuff)

    This is a really good video explaining two tailed tests: http://www.examsolutions.net/maths-r.../example-5.php
    Do you need to find both? My book says OR
    Offline

    22
    ReputationRep:
    (Original post by mp_x)
    Do you need to find both? My book says OR
    Your critical values are given by doing both, yeah. There are some times when you do the other non-critical values method where you can just pick the smaller tail, but if I personally just stick to doing both all the time.
    • Thread Starter
    Offline

    0
    ReputationRep:
    (Original post by Zacken)
    Your critical values are given by doing both, yeah. There are some times when you do the other non-critical values method where you can just pick the smaller tail, but if I personally just stick to doing both all the time.
    Thank you! When using the non-critical values method why would you pick the lower tail and not the upper?
    Offline

    22
    ReputationRep:
    (Original post by mp_x)
    Thank you! When using the non-critical values method why would you pick the lower tail and not the upper?
    You wouldn't! There's be some scenarios where you'd pick the lower and some where you'd pick the higher, it's not always the lower one. You'd need to pick whichever gives you the smallest (or biggest I don't remember since I don't use this method myself) probability since then the other would would necessarily be bigger (or smaller).
 
 
 
  • 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
    Has a teacher ever helped you cheat?
    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.