Advanced SPC - Control Charts

Hi! In the ‘Using Control Charts’ module in Advanced SPC (final BB course), I am confused on how to calculate the UCL and LCLs.

For Q2, is the correct chart IMR as there is only 1 subgroup? Are we looking for the UCL for or x bar MR? How do we calculate this?

For Q3, when I calculate UCL with the p-chart formula, I get 0.133 as UCL. Any ideas what I might be doing wrong?

For Q5, where do I plug “5” subgroups in the UCL formula?

For Q8, how does this differ from Q3?