Calculating Quality Level for a product

#1
Hi

how can i calculate the overall quality level in ppm for a product in the month. this product produced in batches and these batches have different sizes with different quality levels.

for example:

1 batch size: 100000 units with QL =120 ppm defect

2 batch size: 150000 units with QL = 600 ppm defect

3 batch size: 250000 units with QL = 450 ppm defect

4
5
...
...
...


and so on.....


your help is really appreciated
 
#2
For Batch 1, 100000 parts with 120 ppm = 120 defects

For Batch 2, 150000 parts with 600 ppm = 90 defects

For Batch 3, 250000 parts with 450 ppm = 113 defects

Combined the three batchs, i got....

500000 parts with 134 defects with QL = 268 ppm

I am correct??


:confused: :confused: :confused: :confused: