Statistical process control

Apparently a continuation of chapter 6

What is Statistical process control?

A process used to monitor standards by taking measurements and corrective action while a product or service is being produced

3 steps: Monitor, Signal, and Improve

What are 2 causes for varying processes?

Natural causes: random errors that just happen. You can’t have perfect production

Assignable (special) causes: an issue that can be traces to a specific reason. Not a part of the process’s natural behaviour

• bad material, operator, or equipment for example

How would you track SPC in services?

Tracking time and customer satisfaction

What is an attribute?

• A characteristic which is evaluates with a discrete response

• Good/bad; yes/no; correct/incorrect

What is a variable measure

• A characteristic that is continuous and can be measured

• Weight, length, voltage, volume

What does the P-chart tell you

What fraction of products will be defective in a sample

What does c-chart tell you

how many defects per product there are

What does x chart tell you

Detects a shift in the process mean

What does the r-chart tell you

Detects a change in dispersion, independent of the mean