Six Sigma Green Belt Practice Questions

To determine the priority, calculate the risk score for each item: Risk A = 5 (Prob) * 3 (Impact) = 15. Risk B = 1 * 1 = 1. Risk C = 5 * 1 = 5. Risk D = 5 (Prob) * 5 (Impact) = 25. Risk E = 3 * 3 = 9. Risk D has the highest score (25) and therefore represents the highest priority for mitigation.

CPM is a technique specifically used to identify the sequence of critical tasks and determine the minimum time to complete a project. It explicitly maps out task dependencies.

A PERT (Program Evaluation and Review Technique) chart is similar to a CPM diagram in that it visualizes task dependencies and helps identify the critical path. It is often used when task durations are uncertain, using optimistic, pessimistic, and most likely time estimates.

A GR&R study is the standard MSA tool for continuous data. It specifically quantifies the variation from two sources: Repeatability (the variation from one appraiser measuring the same item multiple times) and Reproducibility (the variation between different appraisers measuring the same item). This directly addresses the team's needs.

Cpk is the lesser of Cpu and Cpl. Cpu = (USL - Mean) / (3 * StdDev) = (50 - 48) / (3 * 1.5) = 2 / 4.5 = 0.44. Cpl = (Mean - LSL) / (3 * StdDev) = (48 - 40) / (3 * 1.5) = 8 / 4.5 = 1.78. The Cpk is the minimum of {0.44, 1.78}, which is 0.44. This indicates the process is not capable and is producing defects primarily against the upper specification limit.

A normal probability plot is the most precise tool for assessing normality. It plots the sorted data values against their expected z-scores from a normal distribution. If the data is normal, the points will form a nearly straight line. Deviations from the line indicate skewness, kurtosis, or other departures from normality.

The scenario describes activities in the 'Measure' and 'Analyze' phases of DMADV. In 'Measure', customer needs (CTQs) are identified and translated into measurable design specifications. In 'Analyze', the team analyzes design options and identifies potential failure modes, often using FMEA. IDOV's 'Design' phase focuses more on developing detailed designs after requirements are set, and 'Optimize' involves refining it, often with advanced tools like simulation.

The value stream map clearly shows that the overwhelming majority of the process time is non-value-added (NVA) waiting time (2 + 4 + 3 = 9 hours). The core Lean principle of Flow aims to minimize or eliminate such interruptions and delays, creating a smooth, continuous movement of work. Addressing the waiting times (a form of waste) is the highest priority identified in this map.

Effective Six Sigma projects are tightly linked to organizational goals and key business drivers. Reducing patient admission time directly impacts patient satisfaction, operational efficiency, and potentially patient outcomes, which are core metrics for a hospital. The goal is specific and measurable. Project B is a research/capital project, not a process improvement project, and Project C is not linked to a key business driver.

The primary purpose of the RPN (Severity x Occurrence x Detection) is to prioritize risks and focus improvement efforts on the potential failure modes that pose the greatest risk to the process or product. While an FMEA may be part of regulatory documentation, its core function is risk prioritization, not compliance fulfillment.

A Design FMEA focuses on failures that can occur due to the design of the product itself, such as incorrect material choice, wrong tolerances, or software bugs that affect functionality. A Process FMEA focuses on failures that can occur during the manufacturing or delivery of the product/service, such as incorrect machine setup, operator error, or shipping damage, which are all related to process execution.