Results 1 to 4 of 4

Math Help - standard dev

  1. #1
    Newbie
    Joined
    Apr 2006
    Posts
    2

    standard dev

    "Hai"
    I hope Somebody help me
    2.00.2 - 1.00.2

    (All related to weight")
    Thank you !
    Follow Math Help Forum on Facebook and Google+

  2. #2
    Grand Panjandrum
    Joined
    Nov 2005
    From
    someplace
    Posts
    14,972
    Thanks
    4
    Quote Originally Posted by miavaro
    "Hai"
    I hope Somebody help me
    2.00.2 - 1.00.2

    (All related to weight")
    Thank you !
    I'm not sure that anyone will be able to tell what your question is
    from this but one interpretation (not the most likely, but this is the
    interval arithmetic solution) will give:

    (2 \pm 0.2) - (1 \pm 0.2)=1 \pm 0.4

    RonL
    Last edited by CaptainBlack; April 24th 2006 at 11:43 PM.
    Follow Math Help Forum on Facebook and Google+

  3. #3
    Forum Admin topsquark's Avatar
    Joined
    Jan 2006
    From
    Wellsville, NY
    Posts
    9,939
    Thanks
    338
    Awards
    1
    Quote Originally Posted by CaptainBlack
    I'm not sure that anyone will be able to tell what your question is
    from this but one interpretation (not the most likely) )will give:

    (2 \pm 0.2) - (1 \pm 0.2)=1 \pm 0.4

    RonL
    I would say that equally likely to CaptainBlack's answer would be the answers:

    1) 1.0 \pm 0.2 assuming the standard error in the measuring instrument is 0.2

    2) 1.0 \pm 0.3 using the propagation of errors technique.
    (Define a function f = f(a, b), where we have measurements a = \bar{a}+\delta a and b=\bar{b}+ \delta b. Then \bar{f} = f(\bar{a}, \bar{b}) and \delta f = \sqrt{ \left ( \frac{\partial f}{\partial a} \delta a \right ) ^2 + \left ( \frac{\partial f}{\partial b} \delta b \right ) ^2}. )

    Lacking any other information, my best guess is that the propagation of errors answer (2) is the answer, though there are many statistical reasons for choosing either of the other two. It depends entirely on how the original error estimates were made.

    -Dan
    Follow Math Help Forum on Facebook and Google+

  4. #4
    Newbie
    Joined
    Apr 2006
    Posts
    2

    Post

    thank you
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Replies: 2
    Last Post: March 10th 2011, 01:39 PM
  2. Standard mean
    Posted in the Statistics Forum
    Replies: 1
    Last Post: March 10th 2011, 03:35 AM
  3. Replies: 5
    Last Post: May 18th 2009, 04:14 AM
  4. Replies: 0
    Last Post: October 23rd 2008, 08:03 AM
  5. Standard
    Posted in the Statistics Forum
    Replies: 1
    Last Post: September 17th 2007, 08:21 PM

Search Tags


/mathhelpforum @mathhelpforum