OPMA 3306 MID-TERM EXAM
QUESTIONS & ANSWERS
What are "measures of tendency?" - Correct Answers -Mean, median and mode
What are "measures of dispersion?" - Correct Answers -Range, standard deviation and
variance
Which of the two numbers is larger: 10E7 or 1,000? - Correct Answers -10E7
Which of the two numbers is smaller: 10E-3 or 0.001? - Correct Answers -They are the
same.
How much of a normal distribution is between values located at one standard deviation
above and one standard deviation below the mean? - Correct Answers -68%
Regarding linear regression, the differences between the values predicted by the
regression equation and the actual values in the data set are called? - Correct Answers
-Residuals
In certain data sets, notably economic income, the distribution is said to be "skewed." In
this kind of distribution, the best measure of central tendency is the: - Correct Answers -
Median
Generally speaking, the "skew" in the distribution is usually thought to be because of the
presence of: - Correct Answers -Outliers
What is the relationship of the variance to the standard deviation? - Correct Answers -
The standard deviation is the square root of the variance
Can you add, subtract, multiply and divide standard deviations? - Correct Answers -No
True or False: In linear regression, R-square is the amount of systematic variance that
your linear regression model accounts for: - Correct Answers -True
You are performing a test of statistical inference. In this case, you have a p-value of
0.001. Your alpha level is 0.05. Although you have no way of knowing this, absolutely
no difference of any kind exists between the groups you are testing. The null hypothesis
is true. How would you describe this? - Correct Answers -False positive
, As you make the value of alpha smaller, you can avoid one kind of problem. However,
another kind of problem will become more likely. Pick the right pair of problems, and in
the right sequence (which gets better, which gets worse): - Correct Answers -False
positive; false negative
True or False. In the majority of cases, capacity is typically fluid and easily adjusted to
meet demand as demand fluctuates: - Correct Answers -False
True or False. In exponential smoothing, the term "alpha" is multiplied by an error term
(deviation) calculated by the difference between the previous term's forecast and
previous term's demand: - Correct Answers -True
True or False. We said that, as "n" (the number of periods) of the simple moving
average becomes larger, it starts to approximate the mean of the distribution: - Correct
Answers -True
True or False. Short term forecasts are those forecasts covering periods up to, and
including, two years. - Correct Answers -False. Short term is under 3 months.
Points within the supply chain where inventory is positioned to allow processes or
entities in the supply chain to operate independently: - Correct Answers -Decoupling
points
True of False. In multiplicative seasonal variation, the seasonal amount is constant no
matter what the trend or average amount is: - Correct Answers -False. The seasonal
amount is constant in the additive season variation.
True or False. According to the algorithm provided by the text (and regarding
seasonality), the final step in analyzing seasonality is to "multiply trend component by
seasonal component:" - Correct Answers -True
True or False. A simple moving average can be expressed as a weighted moving
average (WMA) in which all the weights are equal: - Correct Answers -True
True or False. KPI refers to "King pin inclination," an important engineering concept: -
Correct Answers -False. Key performance indicator.
True or False. According to lecture, data points that lie outside of the confidence bands
of the model are outliers: - Correct Answers -True
True or False. In estimating a trend that has a seasonality component, the first step is to
de-seasonalize the data: - Correct Answers -True
True or False. When demand is not predictable, then excess capacity may be needed if
servicing customers quickly is important: - Correct Answers -True
QUESTIONS & ANSWERS
What are "measures of tendency?" - Correct Answers -Mean, median and mode
What are "measures of dispersion?" - Correct Answers -Range, standard deviation and
variance
Which of the two numbers is larger: 10E7 or 1,000? - Correct Answers -10E7
Which of the two numbers is smaller: 10E-3 or 0.001? - Correct Answers -They are the
same.
How much of a normal distribution is between values located at one standard deviation
above and one standard deviation below the mean? - Correct Answers -68%
Regarding linear regression, the differences between the values predicted by the
regression equation and the actual values in the data set are called? - Correct Answers
-Residuals
In certain data sets, notably economic income, the distribution is said to be "skewed." In
this kind of distribution, the best measure of central tendency is the: - Correct Answers -
Median
Generally speaking, the "skew" in the distribution is usually thought to be because of the
presence of: - Correct Answers -Outliers
What is the relationship of the variance to the standard deviation? - Correct Answers -
The standard deviation is the square root of the variance
Can you add, subtract, multiply and divide standard deviations? - Correct Answers -No
True or False: In linear regression, R-square is the amount of systematic variance that
your linear regression model accounts for: - Correct Answers -True
You are performing a test of statistical inference. In this case, you have a p-value of
0.001. Your alpha level is 0.05. Although you have no way of knowing this, absolutely
no difference of any kind exists between the groups you are testing. The null hypothesis
is true. How would you describe this? - Correct Answers -False positive
, As you make the value of alpha smaller, you can avoid one kind of problem. However,
another kind of problem will become more likely. Pick the right pair of problems, and in
the right sequence (which gets better, which gets worse): - Correct Answers -False
positive; false negative
True or False. In the majority of cases, capacity is typically fluid and easily adjusted to
meet demand as demand fluctuates: - Correct Answers -False
True or False. In exponential smoothing, the term "alpha" is multiplied by an error term
(deviation) calculated by the difference between the previous term's forecast and
previous term's demand: - Correct Answers -True
True or False. We said that, as "n" (the number of periods) of the simple moving
average becomes larger, it starts to approximate the mean of the distribution: - Correct
Answers -True
True or False. Short term forecasts are those forecasts covering periods up to, and
including, two years. - Correct Answers -False. Short term is under 3 months.
Points within the supply chain where inventory is positioned to allow processes or
entities in the supply chain to operate independently: - Correct Answers -Decoupling
points
True of False. In multiplicative seasonal variation, the seasonal amount is constant no
matter what the trend or average amount is: - Correct Answers -False. The seasonal
amount is constant in the additive season variation.
True or False. According to the algorithm provided by the text (and regarding
seasonality), the final step in analyzing seasonality is to "multiply trend component by
seasonal component:" - Correct Answers -True
True or False. A simple moving average can be expressed as a weighted moving
average (WMA) in which all the weights are equal: - Correct Answers -True
True or False. KPI refers to "King pin inclination," an important engineering concept: -
Correct Answers -False. Key performance indicator.
True or False. According to lecture, data points that lie outside of the confidence bands
of the model are outliers: - Correct Answers -True
True or False. In estimating a trend that has a seasonality component, the first step is to
de-seasonalize the data: - Correct Answers -True
True or False. When demand is not predictable, then excess capacity may be needed if
servicing customers quickly is important: - Correct Answers -True
