What are common quality issues/errors?
*accuracy vs precision
*repeatability vs reproducibility
How is accuracy defined?
The closeness of agreement between an observed value and an accepted value
How is precision defined?
the closeness of agreement between randomly selected individual measurements or results
How is repeatability (or equipment variation) defined?
the variation in multiple measurements by an individual using the same instrument
How is reproducibility (or operator variation) defined?
the variation in the same measuring instrument when different individuals use it to measure the same parts
Sigma_total^2 = Sigma_processl^2 + Sigma_measurement^2
no answer, just remember that for something ;)
What are the steps to the Nominal Group Technique?
- Recruit 5-10 participants
- ask each to write a problem/issue they feel is important
- gather all info and make a master list
- give list to participants and make them rank the Top 5
- Problems w/ highest points are most important
- discuss results/ make a ranked list
What are the 5 sampling techniques?
*Simple random sampling
*Stratified sampling
*Systematic
*Cluster
*Judgement
What is simple random sampling?
*Every member and set of members has an equal chance of being included in the sample
*Technology, random number generators, or some other sort of chance process is needed to get a simple random sample
*Good bc usually fairly representative since they don’t favour certain members.
What is Stratified random sampling?
*The population is first split into groups. The overall sample consists of some members from every group. The members from each group are chosen randomly.
Example: A student council surveys 100 students by getting random samples of 25 freshmen, 25 sophomores, 25 juniors, and 25 seniors
*Good bc guarantees that members from each group will be represented in the sample
What is Cluster random sampling?
*The population is first split into groups. The overall sample consists of every member from some of the groups. The groups are selected at random
Example: An airline company wants to survey its customers one day, so they randomly select 555 flights that day and survey every passenger on those flights.
*Good bc it gets every member from some of the groups, so it’s good when each group reflects the population as a whole
What is Systematic random sampling?
*Members of the population are put in some order. A starting point is selected at random, and every nth member is selected to be in the sample
Example: A principal takes an alphabetized list of student names and picks a random starting point. Every 20th person is selected to take a survey
What is Judgement sampling?
Using past experience and expertise to make a selection
What is the 100-mile rule?
No one should be called from the meeting unless it is so important that the disruption would occur even if the meeting was 100miles away from the workplace
What is the PDSA Cycle?
Plan
Do
Study
Act
What do you do in the Plan section of the PDSA Cycle?
*Define the process: its start, end and what it does
*Describe the process: key tasks, steps, equipment
*Describe the players (customers, suppliers, operators)
*Define customer expectations
What do you do in the Do section of the PDSA Cycle?
*conduct a study/experiment to test the impact of potential solutions
What do you do in the Study section of the PDSA Cycle?
*Examine the results of the pilot study or experiment
*Determine whether process performance has improved
*Identify further experimentation that may be necessary
What do you do in the Act section of the PDSA Cycle?
*Select the best change or solution
*Standardize the solution
*Implement a plan
*Establish a process to monitor and control process performance
What is a Kaizen event?
an intense and rapid improvement process in which a team throws all its resources into an improvement project over a short time period
What is Poka-Yoke?
an approach for mistake-proofing processes using automatic devices or methods to avoid simple human or machine error such as forgetfulness, misunderstanding etc.
What are the three levels of mistake-proofing?
Design potential errors out of the product or process – Eliminates any possibility that the error or defect might occur
Identify potential defects and stopping a process before the defect is produced – Requires time to stop a process and take corrective action.
Find defects that enter or leave a process – Eliminates wasted resources that would add value to nonconforming work, but clearly results in scrap or rework
What is the default ‘SHIFT’ value in Sigma Level calculations?
1.5 (Assume this value if not explicitly given)
What are benefits of Six Sigma?
*reduces costs by 50% or more
*reduces the waste chain
*improves delivery and quality performance
*provides critical process inputs needed to respond to changing customer requirement
*drives improvements rapidly with internal resources
