Lean Six Sigma Yellow Belt Free Sample Questions

The waste of Motion refers to the unnecessary movement of people (e.g., walking, bending, reaching). In this scenario, the staff members walking to get forms is a classic example of wasted motion. Transportation refers to the unnecessary movement of materials or products, not people.

A Fishbone (or Ishikawa) Diagram is specifically designed for root cause analysis. It helps teams visually organize the potential causes of a problem (the effect) into logical categories (like Manpower, Method, Machine, etc.), which facilitates a structured brainstorming session. SIPOC defines process scope, Pareto prioritizes causes by frequency, and Control Charts monitor process stability over time.

This statement is false. A device that physically prevents an error from occurring is a 'prevention' or 'control' type of Poka-Yoke, which is the most effective form. A 'detection' type would allow the mistake to happen but would immediately signal an alarm or stop the line to alert the operator.

Internal Failure Costs are incurred to remedy defects discovered before the product or service is delivered to the customer. Since the incorrect invoices are being re-issued before being sent out, the associated costs (labor, materials) are categorized as internal failure costs. External failure costs occur after the customer receives the product.

A robust control plan must specify what is being controlled, how it is measured (method and frequency), and what to do if it goes out of control (the reaction plan). The original project champion and the budget from a previous phase are historical data and not active components of the ongoing control plan.

A SIPOC (Suppliers, Inputs, Process, Outputs, Customers) diagram is a high-level process mapping tool used to define the scope of a process. It perfectly matches the requirements described: identifying the suppliers, inputs, process, outputs, and customers. A Value Stream Map includes data on cycle times and waste, and a detailed flowchart would show much more granularity than needed for this initial high-level view.

A Pareto Chart is a bar chart where the values are plotted in descending order of relative frequency, with a cumulative frequency line. Its primary purpose is to apply the Pareto principle (80/20 rule) to highlight the most significant factors in a dataset. This allows the team to focus their efforts on the 'vital few' causes that have the greatest impact.

For skewed data, the median is a more robust measure of central tendency than the mean. The mean is sensitive to extreme values (outliers), so the few very long calls would pull the mean to a higher value that doesn't represent the typical call. The median, being the middle value, is unaffected by these outliers and provides a better picture of the center of the data.

Kanban is a scheduling system for lean manufacturing that signals when to move or produce items. It operates as a 'pull' system, where downstream processes signal to upstream processes when more materials are needed. This prevents the buildup of excess inventory (a form of waste) and ensures production is based on actual demand.

Repeatability is the variation observed when the same operator measures the same part multiple times with the same device. High repeatability indicates that the measurement device (gage) itself is inconsistent. Reproducibility is the variation observed when different operators measure the same part with the same device. Low reproducibility indicates that there is little variation between operators.