If the chance that any of five telephone lines is busy at any instant is 0.01, then what is the
probability that all the lines are busy? - ANS(0.01)^5
Who should complete the control phase after the successful completion and implementation of
the first four phases of DMAIC? - ANSThe complete team is the most desirable option.
To increase the power of experiments, what is the best option in the hands of the Six Sigma
team? - ANSIncrease sample size
Which of the techniques used in DOE helps you in eliminating errors due to nuisance factors? -
ANSBlocking
Hypothesis testing is usually done to: - ANS1) Statistically validate if the sample mean belongs
to the population, 2) statistically validate if means of two groups are the same or if they are
significantly different, and 3) statistically validate if variances of two groups are the same or if
they are different.
What is the concept behind PDCA? - ANSContinuous improvement
What are the experiments called while performing one experiment with five repetitions? -
ANSReplications
Which type of chart is used for small shifts in variation? - ANSCUSUM
What are the distinct types of variation that are displayed in control charts? - ANSChance
(common or random) and assignable (special)
Which of the following is an advantage of the production of a product in large lots? -
ANSMachine efficiencies
A sample is to a statistic as a population value is to a: - ANSParameter
A calculation for reproducibility results in a value of 0 (zero), while repeatability yields a positive
number. Without any other considerations, what conclusion can be made regarding the
reproducibility result? - ANSA reproducibility of zero means there is no operator effect on this
measurement.
The average number of major storms in a city is 2 per year. What is the probability that exactly 3
storms will hit next year? - ANS0.180 or 18%
,Why are scatter diagrams useful in problem-solving? - ANSThey show relationships between
variables.
The advantage of using the modern designed method of experimentation, rather than the
classical OFAT, is that: - ANSFewer terms and measurements are needed for valid and useful
information.
What does ANOVA stand for? - ANSAnalysis of variance
Which quality tool would not be expected to be used during the results confirmation stage of a
problem solution? - ANSFlow chart
Use a process flow chart in the Define and Measure stage.
If 6 consecutive samples were taken from a process and precisely measured, you can still
expect differences. What type of variation would be the most difficult one to determine? -
ANSLot-to-lot variation
Which of the following inference tests does NOT require the knowledge of a test or population
variance? - ANSChi-square test
Which of the following is the LEAST likely candidate to assist in the problem definition stage of
Six Sigma? - ANSControl charts
Control charts are used in the Measure and Control phases. Remember: The process must first
be brought into statistical control by detecting and acting upon special causes of variation. Then
its performance is predictable, and its capability to meet customer expectations can be
assessed (Cp and Cpk), which is done in the Measure phase.
What is the name of the condition if you are running a 7x4 fractional experiment, and you know
factors A, B, C, D, and E are independent of each other, but you suspect factors F and G are
not independent. You conducted a small sub-experiment and discovered a high correlation
between factors F and G. - ANSCollinearity
If P(A) is 0.6 and P(B) is 0.5 and the probability of either event happening is 0.85, what is the
probability of both the events occurring? - ANS0.25 (additive rule)
A process has a high variability and an off-centered mean. What is the first action the team
needs to take? - ANSCenter the mean
What is the use of scatter diagrams? - ANSDisplay correlation
Five samples are drawn out of a population of 200, with each sample being of size 5. The
sample means are 2, 2.5, 3, 2.6, and 4. What is the population mean? - ANS2.8
, In the IT sector, time and effort spent in testing the software, fixing bugs, and retesting would be
considered as what type of waste? - ANSDefects
What is the need to plot data points on the least squares line if a probabilistic regression model
exists? - ANSTo check for fit; there may be a calculation error.
The line fitted to the paired data points must be such that the sum of the squares of the vertical
distances from the points to the line is as small as possible.
A team of Six Sigma has reached the control stage of DMAIC. The team has successfully
reduced the defect of fabric critical stains from 73 to 1 per fabric roll. Now what type of control
chart should the team recommend? - ANSA control chart based on the Poisson distribution such
as the u-chart.
Continuous data:
I-MR Chart (individual data points, destructive testing)
Xbar and R Chart (subgroups)
Xbar and s Chart (subgroups with SD)
Discrete data (constant or varying subgroup size):
np Chart (Defectives, # of units rejected)
p Chart (Defectives, % of units rejected)
c Chart (Defects, # of defects)
u Chart (Defects, average # of defects)
What would be considered the most important element in the deployment of Six Sigma? -
ANSManagement support
What is the attempt to reduce the impact of human error in a process called? - ANSPoka-yoke
What is the major weakness of the one-factor-at-a-time experiment strategy? - ANSIt fails to
account for interactions between factors.
Process capability (Cp) describes a process, often in a stable manufacturing environment,
which leads to the production of a product that conforms to client and design specifications.
What would be the Cp value of an ideal process? - ANSGreater than 1 (>1)
What does OEE stand for? - ANSOverall Equipment Effectiveness
The determination of a temporal variation in multi-vary charting means: - ANSVariation over time
Which of the following pairs is the most useful in preparing control charts, when used together,
for variables data? - ANSX-bar and R
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