1 An airline luggage handling process has a DPMO value of 75

1. An airline luggage handling process has a DPMO value of 75000 where defects are lost bags. Determine the sigma level of their process. Enter a numeric answer only with 2 decimal places: x:xx

2. A hospital pharmacy is operating a sigma level of 3.02. Determine the corresponding DPMO for this process.

Solution

Q1. Sigma level is calculated using the following formula

Sigma = 1.5 + Z value corresponding to the probability (1 - DPO) , where DPO is Defects per Opportunity. It is computed from DPMO as DPO = DPMO / 10⁶

Z value can be computed using Excel formula NORMSINV(p)

where p = 1 - DPMO/10⁶ = 1 - 75000/10⁶ = 0.925

z value corresponding to 0.925 = NORMSINV(0.925) = 1.44

Sigma level = 1.5 + 1.44 = 2.94

Q2. The method of computing DPMO from Sigma level is reverse of the method used in Q1 to compute Sigma level from DPMO

Z value = 3.02 - 1.5 = 1.52 , Probability (p) corresponding to 1.52 = NORMSDIST(1.52) = 0.9357

we know that p = 1 - DPMO/10⁶

Therefore DPMO = (1 - p)*10⁶ = (1 - 0.9357)*10⁶ = 64255