Application of Statistical Tools and Methods Flashcards
In addition to waste there is another basic form of problem, what is it?
It is variation.
Variation is the deviation of single data points within a process.
What is a Six Sigma Black Belt?
A Six Sigma Black Belt is a certified Six Sigma Expert, similar to a certified Lean Consultant being an expert for Lean Consulting.
Overall there several Six Sigma qualification levels (highest on top):
- Six Sigma Champion
- Six Sigma Master Black Belt
- Six Sigma Black Belt
- Six Sigma Green Belt
Decisions are based on the maximum and minimum values
Why is the collection of data important?
The main target of collecting data is to make “things” measurable.
- Improvements can be shown based on a your data collection.
- The data collection is done at the beginning on a project.
- You need to show facts and figures.
- Facts and figures you need to collect in your diagnosis phase.
- You need to present your data (numbers and key performance indicators, KPI) as well.
Why is data within a project important?
- It is important to be clear about the KPIs that can measure the success of the project
- The data within the project is important for a good and accepted baseline.
- Improvements can be shown/proved based on collecting of data at the beginning of the project
- Also quantitative and not only qualitative results are visible!
- The quantitative results mostly convince.
With collected data you can?
You can verify the process
… confirm your hypotheses as vaild
or
… reject them as invalid
What is a UCL?
Upper control limit
What is a LCL?
Lower control limit
Why should we combine Lean and Six Sigma-Tools?
Lean Six Sigma connects the implementation speed of Lean with the precision and high sustainability of Six Sigma.
“Lean Six Sigma“ combines the speed, the way of observation and the implementation orientation from Lean and the discipline of this systematic and the statistical analysis tools from Six Sigma.
What is “pure” lean?
Risk that complex problems and underestimated wrong measures are implemented
What is “pure” six sigma?
Risk that complex analysis are used for simple answers or that simple problems were left behind
What is Lean Six Sigma?
connects the implementation speed of Lean with the precision and high sustainability of Six Sigma.
What is the main difference between Lean & 6 Sigma?
The 4 Proofs
Proof of the Gage repeatability and reproducibility
Proof of main effects
Proof of the improvement of the main KPI
Proof of sustainability
Fast and sustainable results are ensured through the 4 Proofs
Lean focuses on analyzing workflow to reduce cycle time and eliminate waste. Lean strives to maximize value to the customer while using a few resources as possible. Six Sigma strives for near perfect results that will reduce costs and achieve higher levels of customer satisfaction.
What are the 4 proofs?
Proof of the Gage R&R (gage repeatability and reproducibility) and of the baseline
-I have to ensure that the measurement is correct, then I can see if there is a problem or not
Proof of main effects
-What is the biggest lever, were is the root cause
Proof of the improvement of the main KPI
-Is the implemented action successful?
Proof of sustainability
-Is it possible to keep this good result?
Lean Six Sigma tools are used to find what?
the strongest lever in our projects and to reach the targets with less efforts and to stabilize the project results.
What is the basis to improve processes?
Process-oriented thinking
What are the differences between Lean and Six Sigma?
Lean
• High implementation speed
• Sustainability needs to be improved
Six Sigma
• Implementation after lenghty analyses
• High sustainability
Six Sigma uses the power of what to collect data in repetitive processes?
Statistics
What does the “central limit theorem“ in mathematics state?
If you collect enough data, the distribution of it, tends to be a normal distribution (bell curve)
this theorem is the foundation and the assumption that every process has the behavior of a bell curve
Six Sigma is generally not used in which cases?
Six Sigma is in general not used in non-repetitive processes, since it is hard to collect the adequate amount of data.
Focusing in the process in terms of Six Sigma means what?
looking at the process mathematically
What Is the Definition of “Sigma“?
The standard deviation sigma (symbol “σ“) is a measure for the distribution of measured values.
It describes the distance from the mean μ to the inflection point of the curve.
If σ is small, what does the bell curve look like?
The curve is narrow, which means the process has low variation and is performing good.
If σ is large, what does the bell curve look like?
The curve is wide spread, which means the process has high variation and is performing bad.
Why are there additional signmas?
With the addition of several Sigmas, we are able to describe the distribution of the data of a process.
What Six Sigma target did the founders set?
The founders of Six Sigma set the target, that for an almost perfect process a range of 12 Sigma (± 6 Sigma – where the name comes from) should fit within the requirement limits.
That leaves over only 3.4 errors per million operations (defect rate), which indicates, how difficult it is to achieve that target.
How do you apply Six Sigma?
DMAIC-cycle. That stands for Define, Measure, Analyze, Improve and Control
In the DMAIC cycle, what does DEFINE mean?
What is the problem? Detailing the projects Step 1: Project Charter / potential Step 2 : Customer Interview Step 3: SIPOC (Supplier Input Process Output Customer)
In the DMAIC cycle, what does MEASURE mean?
How can we measure the processes?
Trustworthy measurement
- Gage repeatability and reproducibility
- Process capability analysis
In the DMAIC cycle, what does ANALYZE mean?
What can we deduce from the measurement? Determine the significant factors Step 7: Determine the potential X‘s Step 8: Analysis of the X Step 9: Proof of relationship Step 10: Functional relation Y = f (Xi)
In the DMAIC cycle, what does IMPROVE mean?
How can we improve the processes? Improve the main parameters Step 11: Optimal setting of the important X Step 12: Tolerancing X Step 13: Process Capability Y and X
In the DMAIC cycle, what does CONTROL mean?
How can we monitor the process result?
Ensuring the improvements
Step 14: Control Plan
Step 15: Project conclusion
What are some of the main ideas to keep in mind about Six Sigma?
- I can´t improve, what I don´t measure
- Each process has variation
- Mean and variation are needed to make a decision
- Make customer requests measurable
- Find out the main effect
- Effective actions are the best actions (PDCA)
If you collect an infinite amount of data, what will the distribution look like?
- like a normal distribution curve
* like a bell curve
If you achieve a world-class process according to Six Sigma understanding, what’s the defect rate then?
3.4
What different kinds of data types are there?
Continuous Binary Quantity Nominal Ordinal
Continuous data is?
Measurable on the basis of a scale, e.g. Diameter 1.25 mm
Continuous data is data that can take any value.
Height, weight, temperature and length are all examples of continuous data.
Some continuous data will change over time; the weight of a baby in its first year or the temperature in a room throughout the day.
Binary data is?
Ok/Not Okay
Binary data is data whose unit can take on only two possible states, traditionally labeled as 0 and 1 in accordance with the binary numeral system and Boolean algebra
Ordinary data is?
School grades
Ordinal data is a categorical, statistical data type where the variables have natural, ordered categories and the distances between the categories is not known. The ordinal scale is distinguished from the nominal scale by having a ranking.
Quantity data is?
number of errors, number of scratches
Quantitative data is defined as the value of data in the form of counts or numbers where each data-set has an unique numerical value associated with it
Quantitative data is data expressing a certain quantity, amount or range
Nominal (“named”) data is?
Colors
Type of data that is used to label variables without providing any quantitative value
It is the simplest form of a scale of measure
One of the most notable features of ordinal data is that, nominal data cannot be ordered and cannot be measured.
What different kinds of distribution are there?
Normal distribution Poisson distribution Binomial distribution Weibull distribution Exponential distribution
What is normal distribution?
Normal distribution
• Continuous data with a symmetric distribution
• Characteristic “bell shape”
• Our standard distribution
Normal distribution describes continuous data which have a symmetric distribution, with a characteristic ‘bell’ shape.