This question refers to the "Claims Processing" case. A hospital processes claims and the insurance companies often reject them for coding errors. A process improvement team has been working on a project to reduce coding errors for the past $15$ months and the data for the number and type of coding errors can be downloaded from the link provided. Use this data to answer the question below.

Assuming that each claim has $20$ opportunities for errors, what is the sigma level for coding errors in months $1$ and $15?$