Practice Problem 6.3 4 process is found to have a defective rate of 2%. What are the upper and lower control chart limits if you wish to use a sample stce of 100 and consider within 3 sigma Imits? (This data yields itself to a proportion of defects chart). Formula 6.9 page 231. Step 1) Compute P-Bar total number of errors P= Total number records respected Step 2) Next compute the Standard Deviation of defects follows: P(1-12 Step 3) Compute the UCL and LCL of p at 1:3 sigma limits: UCI, - +30, LCL-P-0