Interpolation

Discussion in 'CT5' started by ActStudent, Feb 4, 2007.

  1. ActStudent

    ActStudent Member

    Q&A Bank Solution 3.4 (Page 2, the bit about a**68:60 = 2/5 x 11.372 + 3/5 X 11.849)

    i.e.
    a**68:60 = 2/5 x a**68:63 + 3/5 X a**68:58

    2/5 = (60-58)/(63-58)
    3/5 = (63-60)/(63-58)

    Does anyone know if my understanding about the weighting is correct?

    Solution 3.16 (Page 11)

    a**73:70 = 2/5 X 10.233 + 3/5 X 8.110

    i.e. a**73:70 = 2/5 X a**70:67 + 3/5 X a**75:72
    right? I'm totally lost here. Anyone can explain this in more details? Thanks!
     
  2. Louisa

    Louisa Member

    Yup, agree with you on both counts here.
    I think the thing is we're interpolating in different directions in these two examples.

    In the first case, we have table values for the correct (x=68) but not for the correct (y=60-x-8), so we take the values for x=68 and the two nearest y (y=x-10 and y=x-5) and interpolate between them.

    In the second case, we have table values for the correct age gap (y-x= -3) but not for the correct (x=73). So we take the values for the nearest x (x=70, x=75) and interpolate between those.
     

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