Results are out! Find what you need...fast. Get quick advice or join the chat
Hey! Sign in to get help with your study questionsNew here? Join for free to post

The effect of coding on Sxx/Syy/Sxy?

Announcements Posted on
    • Thread Starter
    • 0 followers
    Offline

    ReputationRep:
    What is the effect of coding data on the values of Sxx, Sxy and Syy. I realise r just remains the same. This is for statistics S1
    • 2 followers
    Offline

    ReputationRep:
    You're not getting much response - so I'll take a stab at this.

    If you add a fixed amount to either the x or y values you will not affect any of Sxx Sxy or Syy because they all subtract the mean.

    If you multiply the x values by say 2 you will quadruple the Sxx value, double the Sxy value and not change the Syy value.
    • Thread Starter
    • 0 followers
    Offline

    ReputationRep:
    (Original post by ian.slater)
    You're not getting much response - so I'll take a stab at this.

    If you add a fixed amount to either the x or y values you will not affect any of Sxx Sxy or Syy because they all subtract the mean.

    If you multiply the x values by say 2 you will quadruple the Sxx value, double the Sxy value and not change the Syy value.
    So it's like variance then; in saying that Var(2X+5)=22Var(X) in the case of Sxx and then for Sxy it's like standard deviation (presumably because the x value isn't squared in an Sxy calculation).

    Thanks for responding
    • 0 followers
    Offline

    ReputationRep:
    (Original post by the.austrian)
    So it's like variance then; in saying that Var(2X+5)=22Var(X) in the case of Sxx and then for Sxy it's like standard deviation (presumably because the x value isn't squared in an Sxy calculation).

    Thanks for responding
    Yes, exactly the same, make sure you square it as you've said

Reply

Submit reply

Register

Thanks for posting! You just need to create an account in order to submit the post
  1. this can't be left blank
    that username has been taken, please choose another Forgotten your password?
  2. this can't be left blank
    this email is already registered. Forgotten your password?
  3. this can't be left blank

    6 characters or longer with both numbers and letters is safer

  4. this can't be left empty
    your full birthday is required
  1. By joining you agree to our Ts and Cs, privacy policy and site rules

  2. Slide to join now Processing…

Updated: May 12, 2012
New on TSR

GCSE English mock revision

Revise together & check out past papers

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