Chapter 9 ? Question 1 4 out of 4 points The following table shows the sales data of server computers of Ziffcore Inc. for the past 5 years. The management plotted the data on a chart. The chart su ...

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Chapter 9
? Question 1
4 out of 4 points
The following table shows the sales data of server computers of Ziffcore Inc. for the past 5
years. The management plotted the data on a chart. The chart suggested that the sales appear to
be increasing in a fairly predictable linear fashion and that the sales are related to time by a
linear function Y
t =240+340t. Using simple linear regression, calculate the forecast for sales in
year 6.
Year Sales
1 580
2 920
3 1260
4 1600
5 1940
Selected
Answer: b.
The forecast for sales in year 6 is more than 2200 but less than or equal to
2400.
Answers: a.
The forecast for sales in year 6 is more than 2000 but less than or equal to
2200.
b.
The forecast for sales in year 6 is more than 2200 but less than or equal to
2400.
c.
The forecast for sales in year 6 is more than 2400 but less than or equal to
2600.
d.
The forecast for sales in year 6 is more than 1800 but less than or equal to
2000.
Response
Feedback: Correct. The forecast for sales in year 6 is more than 2400 but less than or equal
to 2600. Forecast for sales in year 6 is (Y
6 ) = 240 + 340(6) = 2280. Excel
provides a very simple tool to find the best-fitting regression model for a time
series. See 9-4: Regression as a Forecasting Approach
? Question 2
4 out of 4 points
_____ is a common approach to gather data for judgmental forecasts.
Selected
Answer: c.
A survey questionnaire
Answers: a.
Regression analysis
b.
A moving average model
c.

A survey questionnaire
d.
Single exponential smoothing
Response
Feedback: Correct. Common approaches to gathering data for judgmental forecasts are
surveys using questionnaires, telephone contact, and personal interviews. See 9-
5: Judgmental Forecasting
? Question 3
4 out of 4 points
In the context of data patterns in a time series, a(n) _____ is a one-time variation that is
explainable.
Selected
Answer: a.
irregular variation
Answers:
a.
irregular variation
b.
random variation
c.
seasonal variation
d.
cyclical variation
Response
Feedback: Correct. An irregular variation is a one-time variation that is explainable. For
example, a hurricane can cause a surge in demand for building materials, food,
and water. See 9-2: Basic Concepts in Forecasting
? Question 4
4 out of 4 points
A tracking signal provides a method for monitoring a forecast by quantifying _____.
Selected
Answer: c.
bias
Answers: a.
validity
b.
probability
c.
bias
d.
throughput
Response
Feedback: Correct. Forecasters should monitor a forecast to determine when it might be
advantageous to change or update a model. A tracking signal provides a method
for doing this by quantifying bias—the tendency of forecasts to consistently be
larger or smaller than the actual values of the time series. See 9-6: Forecasting in
Practice

? Question 5
4 out of 4 points
A__________is the underlying pattern of growth or decline in a time series.
Selected
Answer: d.
trend
Answers: a.
forecast