A new product's failure rate was predicted to be 2.56 failures per million hours. The test plan was to acccumulate 2,500,000 hours of operational time. What is the maximum number of failures allowed to be 90% confident that the failure rate is 2.56? Using the calculator as indicated, with 3 or fewer failures in 2,500,000 hours, you would be 90% confident that the failure rate is 2.56 per million hours. 
Enter:  l  =  2.56 
 t  =  2500000 
 CL  =  .9 
Press Calculate 
Solves for:  r  =  3 
