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Homework Help: Mean, and standard deviation question.

  1. Nov 11, 2004 #1
    Here's the question:

    so, I said the mean (X) of delta is 0.0015 and the standard deviation (S) of delta is 0.000092

    [tex]X_d=0.0015, S_d=0.000092[/tex]
    [tex]X_l=2.000, S_l=0.0081[/tex]

    I said [tex]Z=d/l\ thus\ X_z=X_d/X_l[/tex] and the [tex]S_z^2=(C_d^2+C_l^2)/X_z^2[/tex]

    So, I did the following: [tex]X_e=X_d/X_l=0.0015/2.000=0.00075[/tex]

    and [tex]S_z=\sqrt{((0.000092/0.0015)^2+(0.0081/2.000)^2)/0.00075^2}=81.956[/tex]

    The last part doesn't seem right though. Any thoughts?

  2. jcsd
  3. Nov 12, 2004 #2


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    Homework Helper

    If you denoted the relative errors by C

    [tex]S_z^2=(C_d^2+C_l^2)*X_z^2[/tex] instead of what you used.
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