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

   2. 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 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]