Statistical Concepts (Statistics for Quality)

• Quality Management System helps a company to meet its regulatory requirements, and make continuous improvements to its operations.
• QMS compares new data with the old ones to know what has been improved.
• Statistics is a vital branch of study in quality management as it helps businesses to understand, quantify, and control the variability in their processes.
• Experiments are essential tools in quality management, and statistics play a crucial role in their design and interpretation.
• Pareto Analysis is a technique used to prioritize and focus improvement efforts by identifying and ranking the most significant factors contributing to a problem.
• Histograms are a graphical representation of the distribution of a dataset, displaying the frequencies of different categories or ranges of data as bars, where the height of each bar corresponds to the frequency of observations within that category or range.
• Scatter Plot is used to visualize the relationship between two variables, helpful in identifying potential correlations or patterns in data and can provide insights into cause-and-effect relationships.
• Regression Analysis is a technique used to prioritize and focus improvement efforts by identifying and ranking the most significant factors contributing to a problem.
• Design of Experiments (DOE) is a systematic approach for investigating and optimizing process or product variables.
• Process Capability Analysis assesses the ability of a process to meet customer specifications.
• Key Metrics in Process Capability Analysis include Cp, Cpk, Pp, and Ppk.
• Process Capability Analysis provides a quantitative measure of how well a process is performing.
• By comparing process capability indices to specification limits, quality managers can determine if the process output is likely to meet customer requirements.
• ISO 9000 is a set of international standards that outline the requirements for a quality management system developed by the International Organizational Standardisation (ISO).
• Fishbone Diagram (Ishikawa or Cause-and-Effect Diagram) is a Six Sigma Tool.
• Six Sigma is a set of management techniques intended to improve business processes by greatly reducing the probability that an error or defect will occur.
• Event is a subset of the sample space such that all the elements in it share a common property.
• Continuous Improvement is supported by Statistical concepts by providing a means to measure performance over time.
• Total Quality Management (TQM) stands as a management philosophy centered on continual enhancement, customer contentment, and the engagement of all staff within an organization.
• Attribute data come from inspection in which the units are classified based on attributes such as finish, color, fit, taste, or smell.
• TQM integrates the following statistical concepts to analyze and enhance organizational processes: Pareto Analysis, Scatter Diagrams, Regression Analysis.
• Measurement data or variable data, come from measurements of characteristics such as length, width, weight, volume, and so on.
• The main principle of SIX SIGMA revolves around the DMAIC model, a roadmap for Six Sigma, used to improve the quality of results that company processes produce.
• Statistical Methodologies that are used throughout the Six Sigma framework: Hypothesis Testing, Design of Experiments (DOE), Measurement Systems Analysis (MSA), Process Capability Analysis.
• Sampling Techniques are often required by ISO 9000 standards to assess the quality of products or processes.
• Frequency distribution (Histogram), Cumulative frequency distribution, Stem-and-leaf diagram, Box-and-whisker plot are graphical tools used in statistical analysis.
• Sample refers to a subset chosen from the population.
• Six Sigma Tools are a data-driven methodology for process improvement.
• Population refers to the collection of all items that are of interest in a given situation.
• Data Analysis is used to analyze data and identify patterns or trends that may impact product quality.
• ISO 9000 helps organizations ensure that their products and services consistently meet customer requirements while continuously improving their processes.
• DMAIC (Define, Measure, Analyze, Improve, Control) is a Six Sigma Tool.
• SIPOC (Supplier, Input, Process, Output, Customer) is a Six Sigma Tool.
• Experiment is a clearly defined procedure that results in observations.
• Quality Metrics are statistical metrics such as mean, standard deviation, and process capability indices used to measure and assess the performance of processes.
• The process capability index is the ratio between the natural tolerance interval and the specification limits.
• A process that has a Cp value greater than or equal to one can be considered capable, while a process with a Cpk value less than or equal to zero cannot be considered capable.
• Cp = Cpl + Cpu
• Process Capability Indices include Cp, Ppk, Cpm, and Ppm.