Business Administration 1220E Lecture Notes - Lecture 4: Control Chart, Sample Size Determination, Type I And Type Ii Errors

• School: Western University
• Department: Business Administration
• Course: Business Administration 1220E
• Professor: Alexander Miller

Document Summary

Otherwise, reject all items in the lot: historical mentality: (cid:498)some degree of poor quality will occur and that is acceptable(cid:499) General steps in spc: define the quality characteristic to measure, attributes: characteristics that are measured qualitatively, thus have discrete values, e. g. Defective/non-defective, # of scratches or blemishes: count both defective and non-defective items--> p-chart, count defective features in an item--> c-chart, variables: characteristics that are measure quantitatively, thus have continuous values, e. g. Weight, length, volume, temperature: difference (range) between smallest and largest values--> b- chart, average--> e-chart, set up a control chart, chart pg. 88, take a random sample and plot the quality measure, chart pg. Stop the process until the quality problem is identified and fix: process improvement tools, discard out-of-control sample observations, may need to revise the control chart. P-chart: control chart for attributes: quality to be measured: proportion of defective items, sample size (n): 30-100 items per sample (guideline, center line: = historical average proportion of defects.