Division (5) The mean squared error of prediction shall be equal to the following:F1

where:

1. (a)

   for all accident years and development years, denotes the cumulative claim estimate in the specific accident year i and development year j, as set out in paragraph 4(c).

2. (b)

   for all development years, S_j denotes for a specific development year j the following amount:

   $$S_j=\sum _{i=0}^{I-j-1}{C}_{\left(\mathrm{i,j}\right)}$$
3. (c)

   for all development years, S′_j denotes for a specific development year j the following amount:

   $${\mathrm{S\prime }}_j=\sum _{i=0}^{I-j}{C}_{\left(\mathrm{i,j}\right)}$$
4. (d)

   for all development years, denotes for a specific development year j the following amount:

    

   where:

   1. (i)

      denotes the development factor estimate of development year j as set out in paragraph 4(c);

   2. (ii)

      denotes the following amount: