CQI study guide
CQI · Work through your exam, one topic at a time.
The ASQ Certified Quality Inspector (CQI) is a foundational credential for inspection professionals who work in support of - and under the direction of - quality engineers, supervisors, or technicians. Certified inspectors apply established body-of-knowledge techniques to evaluate hardware documentation, perform laboratory procedures, inspect products, measure process performance, record data, and prepare formal reports. Candidates need three years of full-time, paid on-the-job experience in one or more areas of the CQI Body of Knowledge. A diploma from a technical, military, or trade school, an associate degree, a bachelor's degree, or a master's or doctorate waives two of those years, and only one such waiver may be claimed. Topics on this exam: Technical Mathematics, Metrology, Inspection and Test, and Quality Assurance and Quality Control. The CQI study guide has 4 sections and about 1,327 words.
01Technical Mathematics for Quality Inspectors
Technical math on the CQI exam is applied, not abstract: converting units, working with tolerances, reading control charts, and computing capability. Be fluent with fractions, decimals, and percent conversions; ratio and proportion; geometry (perimeter, area, volume, circumference, angles); right-triangle trigonometry; and descriptive statistics. Distinguish population notation (μ, σ) from sample notation (x̄, s); the sample standard deviation divides by n−1. Know mean, median, mode, and range, and how a single outlier moves each one.
317 words, about 2 min02Metrology: Measurement Science and Calibration
Accuracy is closeness to the true value (bias). Precision is the repeatability of readings (spread). Resolution or discrimination is the smallest increment the device can display. Uncertainty is a quantified range around a result.
331 words, about 2 min03Inspection and Test
Inspection compares product to requirements by measuring, gauging, or examining; testing applies a stimulus and measures functional response. Know receiving, in-process, and final inspection, first-article inspection, source inspection, and skip-lot. Attribute inspection (go/no-go, visual) is fast and cheap but yields little information; variables inspection produces a distribution that supports capability studies and trend analysis. The classic attribute standard (ANSI/ASQ Z1.4) takes lot size, inspection level, and AQL and returns a sample size and acceptance number.
345 words, about 2 min04Quality Assurance and Quality Control
Quality control is product-focused and detection-based: inspection, testing, measurement, control charts, and disposition of nonconforming material. Quality assurance is process- and system-focused and prevention-based: quality planning, documented procedures, supplier qualification, training, document control, design review, and audits. Question stems usually describe an activity and ask you to classify it - if the activity finds a defect, it is QC; if it prevents defects or verifies the system, it is QA. Four categories: prevention (training, quality planning, supplier surveys, SPC implementation), appraisal (inspection, testing, calibration, audits), internal failure (scrap, rework, re-inspection, equipment downtime), and external failure (warranty, returns, recalls, liability, lost business).
334 words, about 2 min