spc

  1. C

    P charts based on binomial distribution - Statistical Process Control

    Hello all, I have a question related to the use of p-chart in a process where there are defect rates measured. The control limits for this type of chart is calculated with +/- 3 sigmas around the mean (with mean = np and sd = sqrt(n*(1-p)*p)) As it is using i +/- 3 sigmas it assumes that we...
  2. K

    Combining Symmetrized Percent Change (SPC) values

    Hello Talk Stats members, I'm relatively new to statistics, so please let me know if I'm off course! I was wondering if a total symmetrized percent change (SPC) could be calculated from two separate SPC values using weighting as can be done for percent change values. e.g....Total SPC in...