Ted Hessing

[Ted Hessing]

Hi Lori,

My reply above gave the short version. Here is the fuller one, with the ground rule first: I don’t work through questions from other providers’ question banks, the Primer included. Their authors own those questions and their answer keys, so the best place to confirm a specific Primer answer is the Quality Council of Indiana. I’m happy to explain the concept behind it, though, because “spread” trips up a lot of people.

When a question gives you the process spread and nothing else about variation, read the spread as the natural width of the process: 6 standard deviations, or plus and minus 3 sigma. That is the same 6 sigma that sits in the denominator of Cp. So sigma is the spread divided by 6.

From there, Cpk is the distance from the process mean to the nearest specification limit, divided by 3 sigma. Work out both sides (upper and lower) and keep the smaller one. The side closest to its limit is the one that controls Cpk.

The d2 route (sigma = R-bar / d2) is for a different situation: you’re given an average range from subgroups of a known size. If a question gives you no subgroup size, that’s a clue the d2 table isn’t the intended path.

There’s a full walkthrough with worked examples in my Process Capability (Cp and Cpk) article.

Ted

[Ted Hessing]

Hi Reham,

Sorry I’m so late to this one, and welcome. Oscar and Varun have the math right: $7,500 a month x 12 months = $90,000.

Project savings are commonly reported as annualized savings, usually the first 12 months after the change. So when a question gives you a monthly figure, convert it to a year unless it tells you otherwise. That’s also how to spot the distractors: $45,000 is 6 months, $75,000 is 10 months and $120,000 is 16 months.

On a real project, your finance partner usually validates the number and decides what counts as hard savings. There’s more on that in my Financial Measures in Six Sigma article.

Most Green Belt math is arithmetic plus a handful of formulas you use again and again. Practicing a lot, the way you are, is how people get comfortable with it. If you’d like more help with the math itself, I’m building a short course for exactly that, Math Confidence for Six Sigma. Join the waitlist and I’ll let you know when it opens.

Post your next question here any time.

Ted

[Ted Hessing]

Hi Saif,

I’m sorry your question waited this long. The membership options have changed a lot since then, so here’s how Black Belt works today.

• Free Black Belt account. A 75-question ASQ-style practice exam, 9 short topic quizzes and an IASSC-style practice exam, with an explanation for every answer and a score by topic. You can sign up on the free study guides page.
• The full Black Belt study guide. A study guide organized by the exam Body of Knowledge, 2,000+ practice questions, 8 full-length mock exams and access to instructors. Details are on the Pass Your Six Sigma Black Belt page.

Start with the free account either way. Your topic scores will tell you where your gaps are before you spend anything.

For anyone else reading who wants a study group: post here with your exam and your target date so others sitting the same exam can find you. Your local ASQ section is also a good place to meet people preparing for the CSSBB.

Questions about the exam itself are welcome here any time.

Ted

[Ted Hessing]

Hi Andrea,

This one waited far too long for an answer. For anyone preparing for the IASSC Black Belt (ICBB), here’s what IASSC publishes and how I’d use mock tests.

The exam: IASSC describes the ICBB as a 150-question, closed-book, proctored exam with 4 hours allotted, and a minimum score of 70% to pass. The reference document with formulas and tables is provided in the exam session, so you don’t need to memorize formulas. You do need to know which tool fits which situation.

On mock tests: the fact that you kept seeing the same questions everywhere is a warning sign. Many sites recycle one pool, and “braindump” sites claim to sell real exam content. Skip those. They’re often wrong, and using leaked exam content can cost you the certification. A mock test is useful for timing and for finding weak areas, not for predicting the exact questions.

On formulas: if your mocks had few hypothesis test or control chart calculations, don’t assume the real exam will too. Study to the IASSC Black Belt Body of Knowledge and work some problems in every area by hand with an approved calculator.

If you’ve already sat the ICBB, it would help other readers to hear how it went. Post it here.

Ted

[Ted Hessing]

Hi Andrea,

Sorry for the very late reply. There is a shortcut, and you don’t need to write out the whole table.

The rule: resolution is the length of the shortest word in the defining relation. If you’re given the generators, multiply them out (letters that appear twice cancel) and count the letters in the shortest word.

Half fractions (2^k-1): the best design uses all k factors in its one generator, so the resolution equals k.

• 2^9-1: resolution IX
• 2^27-1: resolution XXVII in theory, though nobody runs 67 million trials to get there

Quarter fractions (2^k-2): the best achievable resolution is 2k/3, rounded down.

• 2^8-2: 16/3 rounds down to 5, so resolution V. For example, G = ABCD and H = ABEF give the words ABCDG, ABEFH and their product CDEFGH. The shortest has 5 letters.

I checked both rules by brute force for k from 5 to 10. For smaller fractions (p of 3 or more), use a standard design table.

One more memory aid: in a resolution R design, the orders of two aliased effects add up to at least R. In resolution III, main effects (1) alias with two-factor interactions (2), and 1 + 2 = 3. In resolution IV, main effects alias with three-factor interactions (1 + 3). In resolution V, main effects alias with four-factor interactions, and two-factor interactions alias with three-factor ones (2 + 3).

There’s more in my Partial and Fractional Factorial Design article. Ask here if a specific design is giving you trouble.

Ted

[Ted Hessing]

Hi Mahwish,

A very late answer, but this question still comes up a lot, so here’s where things stand.

IASSC doesn’t hand out the reference document ahead of time as a study file. According to IASSC’s permitted resources FAQ, the IASSC Reference Document is available as a download during the startup steps of your exam session, and you shouldn’t bring your own copy into the session. The same page lists which calculators are allowed. Graphing and programmable calculators, phone calculators and software like Minitab are not.

What that means for your revision: the formulas will be in front of you, but knowing which formula fits which situation won’t be. So practice choosing the tool. Work problems from a written description, without looking up which test or chart to use first.

My IASSC Lean Six Sigma Black Belt study guide page lists every topic on the exam with links to free articles. There’s a Green Belt version too.

Good luck with your revision, and ask here if a topic gives you trouble.

Ted

[Ted Hessing]

Hi Dan,

Sorry this sat unanswered for so long. Good news: you don’t need a reset anymore. Every free practice exam and topic quiz now allows unlimited retakes. Submit the exam, review your answers and the explanations, then retake it whenever you like.

A tip on using retakes well: don’t retake right away. Study the topics you missed first, then come back. Otherwise you end up remembering the answers instead of learning the material, and your score stops telling you anything.

The free practice exams page lists what’s in each exam. If the retake option ever doesn’t show up for you, reply here and we’ll take a look.

Ted

[Ted Hessing]

Hi Jeevan,

Apologies for the very late reply. If you’re looking for a Black Belt guide, the place to start is the exam you’re planning to take, because each certifying body publishes its own Body of Knowledge:

• ASQ Six Sigma Black Belt study guide
• IASSC Lean Six Sigma Black Belt study guide
• Villanova Six Sigma Black Belt study guide

Each page walks through the topics on that exam, with links to free articles on each one. If you haven’t picked a certification yet, my article on the most recognized Six Sigma certifications will help you choose.

To see where you stand, the free Black Belt study guide includes a 75-question practice exam with explanations. There’s also a full Black Belt study guide if you want everything in one place.

Tell me which exam you’re aiming for and when, and I’m happy to point you further.

Ted

[Ted Hessing]

Hi Neil,

I owe you a proper follow-up on this one. The explanation was correct and the grading key wasn’t. The current version of this question keys “Define the value stream” as the correct answer, which matches the explanation.

The reasoning, for anyone who hits this question: you can’t eliminate backlogs, find overlapping functions or study work practices in a value stream until you’ve defined where it starts and where it ends. Defining the value stream always comes first.

Thanks for flagging it. Reports like yours are how the question bank gets better. If you spot anything else in the free practice exams, post it here.

Ted

[Ted Hessing]

Hi Reham,

This one sat here far too long without an answer from me. Here’s how to work it, for you and for anyone else who lands on this thread.

OEE = Availability x Performance x Quality.

• Availability = run time / available time = 6 / 8 = 75%
• Quality = good units / total units = 270 / 300 = 90%
• So Performance = 40.5% / (0.75 x 0.90) = 60%

Performance compares what the line actually made to what it should have made at its ideal rate during the time it ran. 300 units is 60% of ideal, so the ideal output for the 6 hours it ran is 300 / 0.60 = 500 units. That’s an ideal rate of about 83.3 units per hour.

Over the full 8 available hours, that rate gives 83.3 x 8 = about 667 units. That’s the answer to the question as written. Read the wording carefully on exam day, though: “in the available time” points to 667, while “in the time it ran” would be 500.

Quick sanity check: 667 x 40.5% = 270, which is the number of good units. That’s a handy way to think about OEE on the shop floor. It’s good units divided by what a perfect line would have made in the time you had.

There’s more on the three OEE losses in my Total Productive Maintenance (TPM) article.

If anything else in this thread is still bugging you, ask here.

Ted

[Ted Hessing]

Hi Karam,

Sorry this went unanswered for so long. The study group that started this thread ran its course years ago, so here’s how people find study partners today.

• Post right here. Reply on this thread with your exam (ASQ, IASSC, Villanova or another), your target date and what you want from a partner. This forum is public, so other people studying for the same exam can find you.
• Your local ASQ section. ASQ has more than 225 member-led local sections, and many have members preparing for the same certifications.
• Your course forum. If you’re a study guide member, your course forum is the place for questions on specific practice questions and lessons.

One caution on question collections that claim to come from a real exam. Skip them. Certifying bodies treat their exam content as confidential, and those collections are often wrong anyway. You spotted that yourself when you said you weren’t sure the answers were right. Practice questions with worked explanations will do far more for you.

For the Villanova Green Belt, my Villanova Green Belt study guide page lays out what the exam covers. For anyone here preparing for the IASSC Green Belt instead, the IASSC Green Belt study guide page does the same. And the free Green Belt study guide has practice exams with an explanation for every answer.

Good luck, and if you do find a study partner here, let us know how it goes.

Ted

[Ted Hessing]

Dua, all you have to do is log in to your account.

When you log in, you will be at your course home page. There will be dozens of quizzes and tests at the ready. Just click a topic and get started.

[Ted Hessing]

Thanks, Jonathan.

We’ve been slowly improving the pages here on the website to include valuable downloads and graphics. All paid members should be able to access these.

Best, Ted.

[Ted Hessing]

Hi Micheal,

It depends on the examining organization. I would recommend reaching out to them ahead of time.

Calculator. I went with the most basic one imaginable. I only needed it to have an exponential function and a logarithmic / e^n function. My 3 year old has taken a liking to it – once I find where he put it I’ll take a picture and email it to you.

The letter of the law from ASQ is

“Any silent, hand-held, battery-operated calculator with no programmable memory will be permitted. Programmable calculators tend to have graphing capabilities, the ability to store text/alphanumeric data by the input of the user, and a function (fn, F1, F2, etc.) button.” https://asq.org/cert/faq/calculator

From my memory of the ASQ exam no answer walkthroughs were permitted. For example if you had an an illustrated how to solve a Paired T test, that wouldn’t be permitted.

To completely answer your question it was absolutely imperative that I bring my own tables and formula sheets. When I sat the exam, ASQ provided nothing. ASQ’s computer-based exams now include an on-screen scientific calculator, and you can still bring a silent, non-programmable hand-held one. All references must be bound.

As for flash cards, it’s hard for me to answer that without seeing them.

I would follow these principles:

What do I want to have? Bring all of that.

Get there early, review all of your materials with your proctor. Expect several items to be disallowed.

Make sure that you can easily remove objectional material while preserving your other reference material. I personally had a binder and everything with a 3 hole punch on single-sided paper so I could remove anything they wanted.

Bring tons of blank paper. I found it helpful to go through and do all of the questions I knew and/or could easily look up in my references. For everything else I made sure I drew out the whole problem on a single sheet of paper that wasn’t cluttered with anything else on it. That gave me the headspace to reduce the exam to one problem at a time and made my thinking very clear.

[Ted Hessing]

Walid,

Here is how I would work it. Drawing the process first helps.

Step 1, intake: 643 families start. 3 drop out and 50 applications are incomplete, so 590 pass step 1 right the first time. FPY1 = 590 / 643 = 91.8%. 45 of the 50 are completed later (rework) and 5 are lost.

Step 2, eligibility: 635 applications arrive and all are processed. Of the 635 letters, 10 are wrong, so FPY2 = 625 / 635 = 98.4%.

Rolled throughput yield = 0.918 x 0.984 = 90.3%, the chance one application goes through every step right the first time. Traditional final yield = 625 good letters / 643 families = 97.2%, which hides the rework. Some texts call FPY “FTY”; check which your course uses.

You can learn more about the RTY & FPY concepts here.

Best, Ted.

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