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Graphic graduation

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Graphic graduation  (GRAPHIC graduation)

It is occasionally desirable to replace a series of figures by another that shows greater regularity. This process is known as graduation1 or smoothing1, and it generally consists of passing a regular function through a number of points of the time series or other series, such as numbers of persons by reported ages. If a free-hand curve is drawn the process is known as graphic graduation2. Where analytical mathematical methods are used, this is called curve fitting3. A mathematical curve is fitted to the data, possibly by the method of least squares4, which minimizes the sum of the squares of the differences between the original and the graduated series. Other methods include moving averages5 or involve the use of the calculus of finite differences6. Some of the procedures may be used for interpolation7, the estimation of values of the series at points intermediate between given values or for extrapolation8, the estimation of values of the series outside the range for which it was given,

  • 1. graduation n. — graduate v. — graduated adj. smoothing n. — smooth v. —smoothed adj.
  • 7. interpolation n. — interpolate v. — interpolated adj.
  • 8. extrapolation n. — extrapolate v. — extrapolated adj.