Page History

...

Specifies the interpolation method used to compute the percentiles: Nearest Neighbour or Linear. Given a list of numbers V, the algorithm used to compute a percentile is the following.

1.  Compute Compute the rank (R) of a Pth percentile. This is done using the following formula:
   R = P/100 x (N + 1)
   where P is the desired percentile and N is the number of input fields.

2. Compute the percentile:

   1. If R were is an integer, the Pth percentile would will be the number with rank R.

   2. When If R is not an integer, the Pth percentile is computed by interpolation as follows:

      1. If the interpolation method is Nearest Neighbour, the following equation is used:
         Pth = V[int(R + 0.5)]

      2.  If the interpolation method is Linear, the following steps are used:

         1. Define IR as the integer portion of R.

         2. Define FR as the fractional portion or R.

         3. Find the scores with Rank IR and with Rank IR + 1, e.g. V[IR] and v[IR+1]

         4.  Interpolate by multiplying the difference between the scores by FR and add the result to the lower score, e.g.
            Pth = FR * (v[IR+1] - V[IR]) + V[IR]