Considering the 5 customers in point a) and the special Global Customer in point c), for each one of them we know:

Di=the average value of the demand

σdi=the standard deviation of the demand 

where i=1,2,3,4,5 in the case of single customer or GD in the case of global customer.

We have to use the formula for the P2=Fill Rate in the case of Lost Sales P2=1- ESPRCi/(Di+ESPRCi)

Where ESPRC means Expected Shortages for Replenishment Cycle ESPRC=σdi Gu(k).

In the case of P1=80% k=0.8416 and Gu(0,8416)=0.112

in the Case of P1=99% k=2.33 and Gu(0.00352).

the calcule of P2 gives:  


Customers P1=80% P2=99%
1 0.97% 0.999%
2 0.98% 0.999%
3 0.95% 0.998%
4 0.93% 0.997%
5 0.98% 0.999%
Global Demand 0.98% 0.999%