Results 1 to 5 of 5

Math Help - Regressing trending variables

  1. #1
    Senior Member
    Joined
    Apr 2009
    Posts
    289

    Regressing trending variables

    I was wondering what is the effect of say regressing a dependent variable that has a positive trend with an independent variable that has a downward trend?

    Thanks!
    Follow Math Help Forum on Facebook and Google+

  2. #2
    Senior Member MaxJasper's Avatar
    Joined
    Aug 2012
    From
    Canada
    Posts
    482
    Thanks
    54

    Re: Regressing trending variables

    Assume regression y=f(x). Now you say y increases as x decreases?
    Follow Math Help Forum on Facebook and Google+

  3. #3
    Senior Member
    Joined
    Apr 2009
    Posts
    289

    Re: Regressing trending variables

    Sorry what I meant was in a time series context.

    Say you have this regression:

    y_t = b_0 + b_1 x_t where y_t is a positive trending time series variable and x_t is a negative trending time series data, in general would it be a good idea to add a time trend variable if the dependent variable is upwards trending and the independent variable is downwards trending? Ie, use the regression:

    y_t = b_0 + b_1 x_t + b_2 t
    Follow Math Help Forum on Facebook and Google+

  4. #4
    Senior Member MaxJasper's Avatar
    Joined
    Aug 2012
    From
    Canada
    Posts
    482
    Thanks
    54

    Cool Re: Regressing trending variables

    Quote Originally Posted by usagi_killer View Post
    Sorry what I meant was in a time series context. Say you have this regression: y_t = b_0 + b_1 x_t where y_t is a positive trending time series variable and x_t is a negative trending time series data, in general would it be a good idea to add a time trend variable if the dependent variable is upwards trending and the independent variable is downwards trending? Ie, use the regression:
    y_t = b_0 + b_1 x_t + b_2 t
    You are actually talking about these two regressions:

    y(t)-b_1 x(t)=b_0

    y(t)-b_1 x(t)=b_2 t+b_0

    The 1st one doesn't look good!
    Follow Math Help Forum on Facebook and Google+

  5. #5
    Senior Member
    Joined
    Apr 2009
    Posts
    289

    Re: Regressing trending variables

    Thanks for that, why would you pick the 2nd one over the first one?
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Replies: 4
    Last Post: June 27th 2012, 05:46 AM
  2. Replies: 1
    Last Post: October 11th 2011, 02:29 AM
  3. Replies: 1
    Last Post: June 5th 2011, 03:57 PM
  4. variables
    Posted in the Algebra Forum
    Replies: 1
    Last Post: June 12th 2008, 05:09 PM
  5. solve variables in terms of variables
    Posted in the Algebra Forum
    Replies: 4
    Last Post: February 5th 2007, 10:46 PM

Search Tags


/mathhelpforum @mathhelpforum