The document discusses quality control tools used for problem solving. It introduces 7 statistical quality control tools - stratification, Pareto diagram, cause and effect diagram, check sheet, control chart, histogram, and scatter diagram. It provides examples and explanations of how to use Why-Why analysis and What-If analysis as problem solving tools. The document also discusses stratification, Pareto diagrams, and cause and effect diagrams in more detail, explaining their purpose and how they are used to analyze problems and identify countermeasures.