Basic Statistics
A series of links below are listed to teach basic statistics used in Six Sigma projects. A Green Belt, Black Belt, or Master Black Belt should at a minimum be comfortable with these basic statistics. There are primarily two branches in which statistics are studied: Descriptive Statistics Applied to describe the data using numbers, charts, and graphs. Terms such as mean, median, mode, variance, standard deviation are values that summarize data. Descriptive statistics describe the entire group for which the numbers were obtained. These are the actual values for the entire group. Inferential Statistics Uses sample statistics to infer relationships of the population parameters.This is most often done in the Analyze and Improve phases using hypothesis testing, correlation analysis, regression analysis, and design of experiments (DOE). Rarely is it possible to be able to analyze the population (such as the average weight of all sharks in the ocean) so a sampling strategy is employed. The analysis of the sample is used to apply inferences to the entire population. The values may or may not be the same values for the entire population, but they are often used with a confidence interval applied.
A comparison (of means, variance, proportions) is initiated with a hypothesis statement about a population or populations. The sample statistic(s) are studied and analyzed to determine with a certain level of confidence and power that the hypothesis (null hypothesis) is to be proven false or not false (but not necessarily true), see Hypothesis Testing for more information. Comparing Samples vs. Population Measures of Central Tendency: Mean, Median, Mode Measures of Dispersion: Range, Standard Deviation, Variance Alpha and Beta Risks (Type I Error and Type II Error) DPMO - Defects Per Million Opportunities
Process Yield Metrics The meaning and formula around sigma scores Process Capability Indices DISCRETE DISTRIBUTIONS: 3) Hypergeometric Distribution CONTINUOUS DISTRIBUTIONS:
Return to the MEASURE Phase Downloads available for your Six Sigma project Find a career in Six Sigma, active job postings Return to the Six-Sigma-Material Home Page from Basic Statistics
|
