ssadigas

Hi, I need your assistance on judging which Control Chart to consider for Variable Sample Size and Defectives, as I referred few websites which lead me to more confusions since different websites illustrated different Control Charts consideration. Please suggest.

P_Control_Chart.xls I have created a "P Control Chart" in Excel Spreadsheet for different Sample Size. But unable to get the accurate graph as Sample Size varies, the control limits change. In case of "Zero" defects from "x" sample size the process should be "Under Control" whereas the graph depicts "Out of Control" because the LCL is "0.08" but Process "p" is "0.00" (Please see row 8 in attached spread sheet). Likewise, there are couple of other samples where it shows Process is out of control as I am unable to make LCL zero when sample size is varying each time. Please suggest me the way out or facilitate me an excel spread sheet which provides accurate chart when Sample Size Varies each time.