A process that produces titanium forgings for automobile turbocharger wheels is to be controlled through the use of a fraction nonconforming chart.Initially, one sample of size 100 is taken each day for 30 days, and the results showed that a total of 300 items did not conform to specifications.

1. Determine the trial control limits and the centerline using 3-sigma control limits.
2. What is the minimum sample size that can be used for this process and still gives a positive lower control limit (LCL>0)?