Six Sigma Flashcards
What standard deviation does 6 sigma use
Plus or minus 6 standard deviations
The smaller the standard deviation
The smaller variability in the process
A process is capable
When natural process capability fits within the specified tolerance
Capability index
Less than one index indicates the process is not capable
Target capability index
Is 1.33
Risky capability case
Equals 1.00
DMAIC - 5 phases of improvement process within six sigma
Define Measure Analyses Improve Control
Purpose of DMAIC
Improve cycle time, quality and cost
Define consists of
Project charter, process map and voice of the customer
Measure consists of
Understanding process, validate the data accuracy and determine the process capability
Analyze consists of
Process analysis, cause investigation, charter updating , pinpoint and verify causes affecting the problem
Improve consists of
Selects optimal solution, tests a pilot, and implements solutions
Control consists of
Evaluating the process, standardizing the procedures and final actions. Objective is to evaluate effectiveness of the improvement
Statistics
Science deals with collection, tabulation, analysis, interpretation and presentations of quantitative data
Descriptive statistics
Describes characteristics of product or process using info collected on it
Inferential statistics
Draws conclusion about the population based on info contained in a sample. Uses probability
Attribute data
Can only be whole numbers
Variable data
Continuous data. Can be any real numbers. Measured data
Precision
Is determined by how reproducible that measurement value is
Accuracy
Determined by how close a measured value is to its true value
Data described by
Frequency distribution
Measures of central tendency and measures of dispersion
Histogram range
5 to 20. No more than 20
Mean
Average
Median
Middle number
Mode
Most frequently
Central tendency for bell curves
Positively skewed right graph would be where tail falls off is where skew is
Kurtosis
Peakedness of data
Sample data
Info obtained from sample can only be used make plausible conclusions about the population not exact statements
What does six sigma focus on
Reducing variation, measurement defects and improve quality of products, processes and service
