CSSBB Exam Dumps : Certified Six Sigma Black Belt

In DOE terminology, a factor is an input variable that the experimenter deliberately controls or changes to study its effect on a response. For a pie-baking process, cooking time is an input setting and therefore qualifies as a factor. By contrast, flavor, texture, and crust color are typically outputs or response characteristics that result from the chosen factor settings. The CSSBB and related Lean Six Sigma experimental-design materials describe factors as variables adjusted at selected levels, while responses are the measured outcomes used to judge the effect of those settings. For example, time, temperature, ingredient quantity, or oven setting are common factors in a food-processing experiment, whereas quality attributes such as doneness, appearance, and texture are responses. This distinction is fundamental in the Improve Phase because DOE is used to determine which controllable inputs drive desired outputs. A Black Belt must clearly separate Xs from Ys: factors are the Xs and results are the Ys. In this question, cooking time is the only controllable input variable listed, so it is the correct factor in the experiment.

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The correct answer is A. assignable cause variation . In the CSSBB and supplemental SPC materials, the primary purpose of control charts is to distinguish between common cause and special/assignable cause variation. On an X̄-R chart , the X̄ chart is used to detect changes in the process mean, while the R chart monitors within-subgroup variation. The guidance also states that the Range chart should be reviewed first , because if the R chart is out of control, the X̄-chart limits may be suspect.

Since the R chart is designed to signal unusual changes in dispersion, it is especially useful for identifying assignable causes that affect variability, such as changes in material, equipment condition, operator method, or environment. It does not “capture sample size,” and while trends may appear on charts, that is not the primary role of the R chart. Common-cause variation is the natural background variation of a stable process and should not trigger corrective action. Therefore, the best CSSBB-aligned answer is A. assignable cause variation , because the R chart helps reveal special variation in spread.

In DFSS, functional requirements define what the product or service must do and how well it must perform in order to satisfy customer needs and design intent. Their purpose is to establish performance levels that can later be translated into measurable engineering, service, or process characteristics. This is a critical step because customer needs are often expressed in broad or qualitative terms, while functional requirements convert those needs into specific expectations for capability, reliability, speed, capacity, accuracy, or other performance dimensions. Once these requirements are established, the design team can align concepts, specifications, tolerances, and verification methods around them. While functional requirements may also improve communication and reduce redesign indirectly, those are secondary effects rather than their primary purpose. In Black Belt DFSS work, the team must clearly define what the design must achieve before selecting features or building the process that will deliver it. Therefore, the correct answer is A, establish performance levels, because functional requirements provide the performance foundation that guides robust product or service design.

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