After inspecting 900 refrigerators for the possibility of 10 different non-conformances, a total of 55 defects were found. a) How many defects would be expected in a million opportunities (i.e. DPMO)? b) Using the Six Sigma conversion table, what is the estimated yield and sigma level? c) Calculate the rolled throughput yield (RTY) using Method 1. What is the estimated sigma level? If the assembly process consists of three sequential steps with the following yields: Y1 = 98.7, Y2 = 94.3, Y3 = 96.8. d) Calculate the rolled throughput yield (RTY) using Method 2. e) What is the sigma level and DPMO for your answer for d?