This document discusses statistical quality assurance techniques for software. It explains that statistical quality assurance involves collecting information about software errors, categorizing them, tracing each error to its underlying cause using the Pareto principle to identify the most common causes, and correcting problems that led to those errors. Common causes of software defects are then listed, such as incomplete specifications, misinterpreted customer communication, and violations of programming standards. The document states that statistical quality assurance techniques have been shown to significantly improve software quality at some organizations through around a 50% reduction in defects per year. It concludes by introducing Six Sigma as a widely used strategy for statistical quality assurance, originally developed by Motorola, which uses data analysis to measure and improve processes by identifying and eliminating