Discuss the six sigma

hello,I have answered the questions in black and i need you please to answer the red part: 1- step 3 in question 12- 2A3- 3B4- 4 & 5i will attach my answer for question 1 step 1&2 and for 3A. i will attach all things you need.thanks the codes in the answer are just codes that represent initials and stuff like that for the professor.