Lean Six Sigma Green Belt - Practice Exam 3
ACTUAL QUESTIONS AND CORRECT
ANSWERS
What is the variance of a population?
A) It is the difference in creating process maps.
B) It is equal to the sum of the squared deviations from the mean, divided by the population size.
C) It is equal to the standard deviation.
D) It is the sum of the mean, median, and mode. - Correct answers✔B
The variance, σ^2, of a population is equal to the sum of the squared deviations from the mean,
divided by the population size. For a sample, the variance is equal to the sum of the squared
deviations from the mean, divided by the sample size − 1.
T/F We should not try to interpret the X-bar chart if the R chart shows an out-of-control
condition. - Correct answers✔True
We should first investigate the range chart if the control chart meets any out-of-control
conditions. The range chart represents within process variance over time. It is important to fix the
within variation before we interpret the X-bar chart.
In a hypothesis test for means, a sample size of 20 has produced a mean of 9.5 mm with a
standard deviation of 0.5 mm. The customer specification for the part is 10 mm. At 5%
significance level, what should the customer do?
A) State that the population mean is greater than 10 mm.
B) Change their specification to 9.5 mm.
,C) Accept the lot.
D) Reject the lot. - Correct answers✔D
t-value = (9.5 − 10)/(0.5 /sq. rt (20)) = -4.472 t-critical = t(0.025, 19) = - 2.093 (from t-table)
tvalue = -4.472 < t-critical = -2.093. Reject the null hypothesis, meaning the lot mean is not the
same as the target or customer specification. The customer should reject the lot.
Lean originated from:
GE.
Ford.
Toyota.
Motorola. - Correct answers✔Toyota
TPS is the production system developed by the Toyota Motor Corporation to provide the best
quality, lowest cost, and shortest lead time through the elimination of waste. It is known as
"Lean."
What is the minimum number of sample items required to carry out a meaningful Attribute
Agreement Analysis?
10
30
50
15 - Correct answers✔50
,It is recommended to have at least 50 sample items in Attribute Agreement Analysis to establish
appropriate results.
We use Cook's distance statistics to identify unusual data points or observations that
A) have multicollinearity.
B) deviate from the normality conditions.
C) influence the regression fit significantly.
D) Are equally spaced from the center. - Correct answers✔C
Cook's distance statistics is a measure of the distance between the fitted values calculated with
and without the ith observation. It is used to identify the unusual observations that may have
influence on the regression model.
What is the advantage of using EWMA or CUSUM charts over conventional control charts?
Able to detect large process shifts
Easier in calculation
Very accurate
Able to detect small process shifts - Correct answers✔Able to detect small process shifts
EWMA and CUSUM charts are able to detect any small shift (< 1.5 times sigma) in a process,
which is not possible with a conventional Shewhart control chart.
T/F Mixed distributions form if data come from several sources that are expected to be the same
yet are not. - Correct answers✔True
, Mixed distributions are due to the mixing of data coming from two or more different production
lines of the same product.
Stratified random sampling is a method of sampling in which:
A) Every unit has an equal chance of being selected.
B) Groups are created and then units are picked randomly.
C) Clusters are sampled every nth time.
D) Every nth unit is selected from the population. - Correct answers✔B
Stratified random sampling is a method of sampling in which strata/groups are created and then
units are picked randomly.
Who is famous for the introduction of DFSS?
Bob Galvin
Jack Welch
Edwards Deming
Jim Womack - Correct answers✔Jack Welch
Jack Welch of General Electric (GE) started DFSS in 1995 for developing new products and
services, as well as for redesigning processes, products, and services.
Who should construct the control plan?
Sponsor
ACTUAL QUESTIONS AND CORRECT
ANSWERS
What is the variance of a population?
A) It is the difference in creating process maps.
B) It is equal to the sum of the squared deviations from the mean, divided by the population size.
C) It is equal to the standard deviation.
D) It is the sum of the mean, median, and mode. - Correct answers✔B
The variance, σ^2, of a population is equal to the sum of the squared deviations from the mean,
divided by the population size. For a sample, the variance is equal to the sum of the squared
deviations from the mean, divided by the sample size − 1.
T/F We should not try to interpret the X-bar chart if the R chart shows an out-of-control
condition. - Correct answers✔True
We should first investigate the range chart if the control chart meets any out-of-control
conditions. The range chart represents within process variance over time. It is important to fix the
within variation before we interpret the X-bar chart.
In a hypothesis test for means, a sample size of 20 has produced a mean of 9.5 mm with a
standard deviation of 0.5 mm. The customer specification for the part is 10 mm. At 5%
significance level, what should the customer do?
A) State that the population mean is greater than 10 mm.
B) Change their specification to 9.5 mm.
,C) Accept the lot.
D) Reject the lot. - Correct answers✔D
t-value = (9.5 − 10)/(0.5 /sq. rt (20)) = -4.472 t-critical = t(0.025, 19) = - 2.093 (from t-table)
tvalue = -4.472 < t-critical = -2.093. Reject the null hypothesis, meaning the lot mean is not the
same as the target or customer specification. The customer should reject the lot.
Lean originated from:
GE.
Ford.
Toyota.
Motorola. - Correct answers✔Toyota
TPS is the production system developed by the Toyota Motor Corporation to provide the best
quality, lowest cost, and shortest lead time through the elimination of waste. It is known as
"Lean."
What is the minimum number of sample items required to carry out a meaningful Attribute
Agreement Analysis?
10
30
50
15 - Correct answers✔50
,It is recommended to have at least 50 sample items in Attribute Agreement Analysis to establish
appropriate results.
We use Cook's distance statistics to identify unusual data points or observations that
A) have multicollinearity.
B) deviate from the normality conditions.
C) influence the regression fit significantly.
D) Are equally spaced from the center. - Correct answers✔C
Cook's distance statistics is a measure of the distance between the fitted values calculated with
and without the ith observation. It is used to identify the unusual observations that may have
influence on the regression model.
What is the advantage of using EWMA or CUSUM charts over conventional control charts?
Able to detect large process shifts
Easier in calculation
Very accurate
Able to detect small process shifts - Correct answers✔Able to detect small process shifts
EWMA and CUSUM charts are able to detect any small shift (< 1.5 times sigma) in a process,
which is not possible with a conventional Shewhart control chart.
T/F Mixed distributions form if data come from several sources that are expected to be the same
yet are not. - Correct answers✔True
, Mixed distributions are due to the mixing of data coming from two or more different production
lines of the same product.
Stratified random sampling is a method of sampling in which:
A) Every unit has an equal chance of being selected.
B) Groups are created and then units are picked randomly.
C) Clusters are sampled every nth time.
D) Every nth unit is selected from the population. - Correct answers✔B
Stratified random sampling is a method of sampling in which strata/groups are created and then
units are picked randomly.
Who is famous for the introduction of DFSS?
Bob Galvin
Jack Welch
Edwards Deming
Jim Womack - Correct answers✔Jack Welch
Jack Welch of General Electric (GE) started DFSS in 1995 for developing new products and
services, as well as for redesigning processes, products, and services.
Who should construct the control plan?
Sponsor
