Six Sigma 1.23

What are the characteristics of a control plan?

- A control plan may address a product or one or more related processes - Checking, monitoring, and response activities are included in the control plan - A control plan is an accessible, single document summary - Each control plan includes information on frequency and method of measurement, as well as miscellaneous info such as notes and meeting minutes

Which examples of variables are well suited for SPC?

- A financial institution wants to minimize the processing time for each of its loan applications - A six sigma team wants to find a way to reduce employee absenteeism to the industry benchmark - A team member doing charting can easily measure when user error causes a machine malfunction - An accounting department specifies that invoice errors should be minimized to 0.01% in the next year

Which statements accurately describe Statistical Process Control?

- All members of the team have to buy into the program - SPC's focus isn't on human issues but rather process issues - Control charts are the most preferred tools in SPC - To properly implement SPC, you should avoid overanalyzing to the detriment of process control - To reduce variation in a process by improving and controlling process performance - To monitor performance in order to assess how a process compares to its control limits - To use statistical analysis to help identify sources of variation

Which actions are important in transferring responsibility for control from the Six Sigma team to the process owner?

- Establishing clear documentation procedures for the control process - Updating all work instructions to ensure a consistent response if the process drifts out of control - Securing understanding and commitment from those workers doing the monitoring - Integrating the control plan with other processes it may affect

What are accurate statements related to determining appropriate subgroup size?

- Large subgroups may contain special cause variation or dependent data - The Six Sigma team must have a sufficient history of the process when selecting subgroup size - The optimum number and size of subrgroups depend on the size of the process shift you wish to detect - Service processes usually have a sample size of one

What are some of the criteria for choosing variables to study?

- Represent a critical dimension of the product or process - Known special or root cause variation

What are some of the examples of information typically included in the main body of a control plan?

- The USL is 4.11 mm and the LSL is 2.55mm - If the specifications are exceeded more than 3x per hour, contact Louie at extension 21 - Machine operatiors will take measurements - A micrometer will be used to take measurements

What are the objectives of Statistical Process Control?

- To distinguish between special and common cause variation by examining runs of data and tracking trends exhibited on control charts - To access how a process compares to its control limits by monitoring its performance - To control and improve process performance to reduce variation in the process

How can you tell when a process is out of control?

- You're not getting a repeatable output in terms of your mean and standard deviation - Some points on the control chart are outside the control limits

To find any special cause variations in your data, the data needs to be highly representative of the population. That's why you need rational subgroups.What are the properties of rational subgroups?

-Observations within a subgroup are from a single, stable process - Obersvations are made up of independent data points - Observations are taken in a time ordered sequence

A recent string of defects have been traced back to a poor batch of raw materials. What type of variation is this?

Special cause variation