DEFINE Phase

The following are example questions that will test your knowledge of the concepts within the DEFINE phase of a DMAIC and DFSS Six Sigma project.

1) The customer specifications for a process, also referred to as the Voice of the Customer, will provide which of the following. There may be more than one correct answer.

A) Upper Control Limit - UCL
B) Target value within the specification limits
C) Upper Specification Limit - USL
D) Lower Specification Limit - LSL
E) Lower Control Limit - LCL

Answers: B,C,E

Choices A and E are a function of the process, the goal is to have the voice of the process (VOP) perform within the voice of the customer (VOC) specifications. You may get one, two, or all three of the customer specifications and they may also provide attribute information, and more.

2) Which of the following are characteristics of the inputs to a process.

A) these are referred to as the x variables
B) these are the "causes" that create the effect
C) these are the variables the team seeks to monitor
D) A process output is a function of its inputs

Answer: A,B,D

C is a characteristic of the effect, or y-variable. The team wants to CONTROL the inputs and MONITOR the outputs.

3) Inferential statistics is

A) statistics derived from analyzing population
B) inferring population parameters from samples of data
C) inferring sample statistics from population parameters

Answer: B

4) The Weighted Average Cost of Capital is commonly used to evaluate capital projects. The WACC is also known as what other terms, there may be more than one answer.

A) Cost of Capital
B) Hurdle Rate
C) Discount Rate
D) Interest Rate

Answer: A,B,C are all commonly used and interchangeable terms with WACC.

Projects should exceed the WACC which is the cost of raising funds for a capital funding project according to your firm's targeted capital structure.

5) Pareto charts are very commonly used in Six Sigma projects, often in many phases and throughout all facets of a business. Which best describes the Pareto Chart.

A) A timeline indicating the progression of the project
B) A risk analysis of input variables
C) A chart used to plot occurrences of categorical data
D) A trend analysis chart to predict future response

Answer: C

A Pareto chart is usually a vertical bar chart with occurrences on the y-axis and the categories along the x-axis. The are usually sorted with the highest or most frequent category on the left side and going right in descending order.

6) The tool used to ensure that all effected people are involved and engaged is the

A) Stakeholder Analysis
B) Gannt Chart
C) Project Contract
D) Prioritization Matrix

Answer: A

7) The tool used to organize information about complex or unfamiliar topics for which the team may have little knowledge is

A) Prioritization Matrix
B) Gantt Chart
C) Affinity Diagram
D) CTQ Diagram

Answer: C

The affinity diagram is the simplest brainstorming exercise that visually organizes ideas and like concepts. It is easy to use and can get the team moving forward together by bringing out each person's input, thoughts, and questions.

MEASURE

1) If more than 25% of the points on a R-chart are equal to zero than this is most likely a problem with what part of the measurement system?

A) Stability
B) Repeatability
C) Reproducibility
D) Resolution
E) Linearity

Answer: D

The measurement system should record data ten times greater than will be used in project metric. If you are using feet as a unit of measurement for your metric, then take all your measurements in inches (this is 1/12 resolution) and satisifies the 10-bucket rule.

If you are using a metric measured in X.XX (hundredths), then record all your measurements in X.XXX (thousandths)

What else may indicate poor gage resolution? Plateaus (flat spots) of the data on the r-chart and if r-bar is too small

2) Repeatability is variation "within", and reproducibility is the variation "among" or "between all".

A) True
B) False

Answer: True

Repeatability would describe the variation within one appraisers own assessments across multiple assessments. Answers the question of how repeatable are his/her answers each time assessing the same thing.

3) Sampling taken of the first 100 patients in a hospital directory listed by alphabetical order is known as

A) systematic random sampling
B) random sampling
C) stratified random sampling
D) convenience sampling

Answer: D

4) A sampling strategy that employs a system such as using every 20th part that comes from a machine is an example of

A) systematic random sampling
B) random sampling
C) stratified random sampling
D) convenience sampling

Answer: A

5) A measurement of lumens, decibels, temperature, and ohms, are examples of

A) continuous data
B) attribute data
C) locational data
D) discrete data

Answer: A

6) Which subjective analysis tool is used to visualize the relationships between many inputs, x's, and an output, Y. This tool focuses on the causes, not the symptoms.

A) Cause and Effect (Prioritization) Matrix
B) Fishbone (Ishakawa) Diagram
C) FMEA
D) Run chart

Answer: B

The Fishbone is usually the first in a line of subjective tools to help reduce the trivial many inputs into the vital few inputs that cause the effect (Y). The next tool can be the C/E Matrix or the FMEA.

7) Which of the following yield metrics does not account for rework or hidden factory loss.

A) Rolled Throughput Yield
B) RTY
C) Normalized Yield
D) TPY
E) Final Yield

Answer: E

Final Yield (FY) does not account for the hidden factory or rework. It is simply the final number of acceptable pieces at the end divided by the quantity started in a process. It does not tell you how many were reworked at each step of the process.

8) If there are 11 orders, and each order has 2 items, and there are 3 opportunities for a defect (such as incorrect item, wrong price, and damaged), then how many total opportunities are there for a defect?

A) 22
B) 11
C) 66
D) 33

Answer: 66

9) Which of the following are types of errors in conducting a survey or other methods of gathering the Voice of the Customer (VOC)?

A) Coverage error
B) Nonrespondent error
C) Sampling Error
D) Measurement Error
E) All of the above

Answer: All of the above

10)What is the probability that Z is greater than or equal to -1.96 and smaller than or equal to -1.4. Z is a standard normal random variable?

A) 0.9821
B) 0.0555
C) 0.0558
D) 0.98

Answer:0.0558

Reference the Z-table to help solve.

ANALYZE

1) Type I error and Type II error are respectively known as

A) P-value risk
B) Confidence Interval and Power risk
C) Alpha and Beta risk
D) Consumers Risk

Answer: C

Alpha risk is known as Type I Error = Alpha Risk = Significance Level = Producers Risk = False Positive.

Type II Error = Beta Risk = Consumers Risk = False Negative

2) While ANOVA is "Analysis of Variance", it is used for which reason?

A) Testing variances of two populations
B) Testing variance of two or more populations
C) Testing capability of process
D) Testing means of a population

Answer: D

ANOVA assumes homogeniety of variance which means the variance within each factor are equal.

3) What other assumption(s) are required to use ANOVA:

A) Measurement system is linear and reproducible
B) Data sets are normally distributed
C) Data sets have equal means
D) Data sets have equal variances

Answer: B,D

Choice A is already confirmed, you should have an adequate measurement system as verified in the MEASURE phase. Choice C is the reason for using ANOVA, which is a test of the equality of the means (can be used like the student t-test to test the equality of two means).

4) Confidence Intervals are not always symmtrical, but what is true about confidence intervals when the sample size changes.

A) As sample size, n, decreases the confidence interval spread increases.
B) As sample size, n, increases the confidence interval spread decreases.
C) The sample size, n, does not affect the confidence interval.

Answer: A,B.

The larger the width, or spread, of thr confidence interval the weaker the estimate of the mean or variance. Logically, the more data and samples taken within a population, the more confidence you will have in estimating the population mean or variance. As n approaches infinity, the sample average approaches the population mean.

5) The standard deviation of a standard normal distribution is

A) always equal to one
B) is always equal to zero
C) can be any positive value
D) can be any negative value

Answer: A

The standard deviation of a standard normal distribution is always equal to one.

6) Which of the following are characteristics of the normal probability distribution?

A)89% of the time the random variable assumes a value within plus and minus 2 standard deviation of its mean
B)Symmetry
C)The total area under the curve is always equal to 1
D)99.72% of the time the random variable assumes a value within plus or minus 3 standard deviation of its mean

Answers: B,C,D

IMPROVE

1) A four level, three factor, DOE is being conducted but due to time and budget constraints a half factorial is used. What will be the number of treatment combinations?

A) 64
B) 16
C) 41
D) 32

Answer: D

Recall that factors are the power which the levels are raised. Four cubed is 64, and a half factorial means that half of the full factorial combinations will be used, which is 32.

2) Which of the following are true of the Evolutionary Operations (EVOP):

A) Used when process is not in control
B) Limited to two or less input variables
C) high experimental risk
D) uses large samples sizes to detect small experimental differences.

Answer: D

EVOP is evolutionary in that it learns from existing behaviors to predict future treatments to improve the response. It is normally used when a process is in statistical control.

3) Waste Elimination is a key component of the IMPROVE phase and will involve cultural transformation and high assurance that team members and affected stakeholders are ready to change. What tools are commonly used (not all depending on the project) at this time.

A) Stakeholder Analysis

B) Takt Time / Operator Balance Charts
C) SPC
D) Kanban / Pull Principles
E) Standard Work
F) Visual Management
G) Implementation of TPM
H) ANOVA
I) SMED

Answer: All choices EXCEPT C and H

4) The goal of IMPROVE is to make a fundamental change or prove through trials that a fundamental change is possible by eliminating waste and determining the relationship of the key input variables that affect the outputs of the process. When a process is in statistical control what are possible steps to improve it to a better desired performance level.

A) Target and resolve the special causes
B) Minimize the common cause variation
C) Influence the customer to open up their specification limits
D) Open up the process control limits

Answer: B

The special causes must be eliminated to have an statistically controlled process. It may be possible that a customer has unrealistic specifications or those that are too tight that it is not practical or financially viable, it may be possible to work with them and prove through testing and validation that the specifications can be opened or changed. It is not possible to select these values as you would like them, they are set by a formula through the process itself, they represent the Voice of the Process.

CONTROL

1) Which of the following tools is handed off from the Six Sigma Black Belt (or other Belt) to the Process Owner after control of the effect has been established and statistically proven?

A) Pareto
B) Prioritization Matrix
C) DOE
D) Control Plan
E) Gantt Chart

Answer: D

The process owner uses this to help monitor and react to Y and its behavior after the project is formally closed.

2) Which of the following are characteristics of the RPN? There may be more than one answer.

A) The lower the value the lower the risk to the project output, Y.
B) it equals the SEV * DET * OCC
C) it is found on the FMEA as subjective analysis tool
D) it is compared to the P-value to make a decision on null hypothesis.

Answer: A,B,C

It is also the EFFECTS * CAUSES * CONTROLS - which is another way of saying the SEV * DET * OCC

3) With 50 samples (n=50), a process has a p-bar of 0.25. What are the upper and lower three sigma limits (UCL/LCL)?

A) 0.25 and -0.25
B) 12.5 and -12.5
C) 21.69 and 3.31
D) 15.56 and 9.44

Answer: C

Must use the formula to calculate the NP Chart control limits.

4) Which of the following a characteristics of the C-Chart, there may be more than one choice?

A) Plotting number of Defects
B) Plotting continuous data
C) Poisson assumptions satisfied
D) Fixed sample size (constant)

Answer: A,C,D

Visit C Chart for more information.

4) Which type of chart (of the choices below) is typically used when plotting continuous (can apply to attributes data) data to detect small changes over a small period of time? The moving average smoothes the variation of time therefore should not be used when looking for a point that is outside of the process control limits.

A) I-MR
B) X-bar, R
C) EWMA
D) U-Chart

Answer: C

Visit Exponentially Weighted Moving Average Chart for more information. The most recent data point is given the most weight and as time progresses the weight of the older points decreases. The term exponentially means that the weights of the older points decrease exponentially with time. CUSUM charts use equals weights for previous data points.