This is a draft cheat sheet. It is a work in progress and is not finished yet.
Seven QC Tools (Q7)
Statistical approach and visual approach are key-points. Graphs are important.
Pareto Chart:** Combination of bar chart and accumulation distribution chart
Histogram:** Graphs of Distribution for 1-dimension data
Graph : Bar chart, line chart, pie chart, etc.
Scatter Diagram:** Graphs of Distribution for 2-dimension data. To check the relationship of two characteristics
Cause-and-Effect Diagram:** Systematic diagram of cause and effect. Similar to mind-mapping.
Check Sheet:** A list of check points.
Control Chart:** A kind of line chart. X-dimension is time. To check the stability of the movement of data.
Some people say that "control chart" is one of the "graph" and stratified sampling is one of the seven QC tools.
New Seven QC Tools (N7)
New seven QC tools are made to analyze non-quantity information (knowledge) mainly. Those tools are could be said as reasoning methods.
Affinity Diagram: Grouping of the idea of Brainstorming
Relation Diagram: Diagram of Why-why analysis. It is good to use if cause-and-effect contains circulation structure
Tree Diagram: Collection of plans and methods systematically.
Matrix Diagram: A matrix to express the strongness of relationship between two things. Basic of QFD (Quality Function Deployment)
Arrow Diagram: Same to PERT
Process Decision Program Chart (PDPC): Same to "Flow chart"
Matrix Data Analysis: Same to Principal Component Analysis
Weakness of Q7 and N7
Most of Q7 are tools for quantity data analysis. But Check-Sheet and Cause-and-Effect Diagram are for knowledge analysis.
Most of N7 are tools of knowledge analysis. But Matrix-Data-Analysis is for quantity data analysis. And it is mathematically too difficult to study for beginners.
From other viewpoint, Q7 and N7 are not only for Quality Study today because they are introduced as useful tools for various business use. So the name, "QC", is not suitable.