I work for a manufacturing facility and we use a program called Minitab which is a statisical program that generates charts and capabilities based on the data received. I need help trying to figure out how Minitab is calculating a variable called Rbar. Attached you will see some sample charts where the Range is calculated. The value Minitab is getting is .00821 where when I do it manually I am getting .0115. I need to figure out how and why there is a variation in the values as I need to run some calculations manually.
First person that can explain this to me and how me how I can get .00821 will win the project. I only have $30 to spend on this so please bid accordingly.
Attached is the outputted graphs as well as a csv file containing the data points. (use subgroup sizes of 3 as you can see from the graphs)
I have decided to give up on figuring out the difference between my calculated Rbar version and the one in minitab. To now win the project I would now want to generate the process capability histogram as seen in the attachment. I need to know how to calculate the datapoints that are created on the graph as well as the number of bars on the graph as well. If you have any questions let me know.