Question 1

To create a seasonally adjusted time series,divide the time series by the seasonal ____________________.

Accepted Answer

The answer of To create a seasonally adjusted time series,divide...

Question 2

Holiday Hours
The total holiday hours (in 1000s)were recorded for 16 quarters in a large steel mill as shown below.
 $$\begin{array} { | c | c c| } 
\hline \text { Year } & \text { Quarter } & \text { Overtime Hours } \
\hline 2011 & 1 & 32 \
& 2 & 15 \
& 3 & 21 \
& 4 & 28 \
\hline 2012 & 1 & 35 \
& 2 & 16 \
& 3 & 27 \
& 4 & 29 \
\hline 2013 & 1 & 36 \
& 2 & 21 \
& 3 & 25 \
& 4 & 37 \
\hline 2014 & 1 & 41 \
& 2 & 29 \
& 3 & 31 \
& 4 & 40 \
\hline
\end{array}$$
-{Holiday Hours Narrative} Calculate the seasonal indexes based on the regression trend line in the previous question.

Accepted Answer

The answer of Holiday Hours
The total holiday hours (in 1000s)were...

Question 3

In determining monthly seasonal indexes for natural gas consumption,the sum of the 12 means for gas consumption as a percentage of the moving average is 1195.To get the seasonal indexes,each monthly mean is to be multiplied by (1195 / 1200).

Accepted Answer

A) True 
 B)False

Question 4

Forecasts based on trend and seasonality are generated by:

Accepted Answer

A)  identifying and removing the seasonal effect 
B)  extrapolating the linear trend 
C)  adjusting the forecasts to the seasonal effect 
D)  All of these choices are true.

Question 5

The time-series model yt = Tt * Ct *St * Rt is used for forecasting,where Tt,Ct,St,and Rt are respectively the trend,cyclical,seasonal,and random variation components of the time series,and yt is the value of the time series at time t.The following estimates are obtained: $\tilde { T} _ { 1}$ = 120, $\tilde { C } _ { t }$ = 1.02, $\tilde { S } _ { t }$ = 0.95,and $\hat { R } _ { 2 }$ = 0.90.The model will produce a forecast of:

Accepted Answer

A)  122.870 
B)  104.652 
C)  116.280 
D)  102.600

Question 6

The number of four-period centered moving averages of a time series with 20 time periods is:

Accepted Answer

A)  16 
B)  20 
C)  24 
D)  28

Question 7

The trend line $\hat { y }$ = 0.70 + 0.005t was calculated from quarterly data for 2011-2015,where t = 1 for the first quarter of 2011.The seasonal indexes computed from the trend line for the four quarters of the year 2016 were .85,1.05,1.15,and .80,respectively.The seasonalized forecast for the third quarter of the year 2016 is:

Accepted Answer

A)  0.937 
B)  0.820 
C)  0.815 
D)  0.943

Question 8

Smoothing time series data by the moving average method or exponential method is an attempt to dampen the effects of seasonal variation.

Accepted Answer

A) True 
 B)False

Question 9

A time series is:

Accepted Answer

A)  a set of measurements on a variable collected at the same time or approximately the same period of time. 
B)  a set of measurements on a variable taken over some time period in sequential order 
C)  a model that attempts to analyze the relationship between a dependent variable and one or more independent variables 
D)  a model that attempts to forecast the future value of a variable

Question 10

Daily Sandwich Sales
The daily sales figures shown below have been recorded in a sandwich shop.
 $$\begin{array}{l}
\quad\quad\quad\quad\quad\quad\quad\quad\quad\text { week}\
\begin{array} { | l | c c c c | } 
\hline \text { Day } & 1 & 2 & 3 & 4 \
\hline \text { Manday } & 38 & 46 & 35 & 59 \
\text { Tuesday } & 40 & 36 & 52 & 53 \
\text { Wednesday } & 17 & 32 & 25 & 28 \
\text { Thursday } & 20 & 17 & 28 & 33 \
\text { Friday } & 26 & 20 & 32 & 20 \
\hline
\end{array}
\end{array}$$
-{Daily Sandwich Sales Narrative} Compute the three-day and five-day moving averages.

Accepted Answer

The answer of Daily Sandwich Sales
The daily sales figures shown...

Question 11

The mean absolute deviation averages the absolute differences between the actual values of the time series at time t and the forecast values at time:

Accepted Answer

A)  t + 1 
B)  t 
C)  t - 1 
D)  t - 2

Question 12

The effect of an unpredictable,rare event will be contained in which component of the time series?

Accepted Answer

A)  Long-term trend 
B)  Cyclical variation 
C)  Seasonal variation 
D)  Random Variation

Question 13

We compute the three-period moving averages for all time periods except the first and the last.

Accepted Answer

A) True 
 B)False

Question 14

The most commonly used measures of forecast accuracy are ____________________ and the sum of squares for forecast errors (SSE).

Accepted Answer

The answer of The most commonly used measures of forecast...

Question 15

The following is the list of mean absolute deviation (MAD)statistics for each of the models you have estimated from time-series data: $$\begin{array} { | l | c | } 
\hline \text { Model } & \text { MAD } \
\hline \text { Linear Trend } & 1.38 \
\text { Quadratic Trend } & 1.22 \
\text { Eigdonental Trend } & 1.39 \
\text { Autorepressive(2) } & 0.71 \
\hline
\end{array}$$ Based on the MAD criterion,the most appropriate model is

Accepted Answer

A)  linear trend 
B)  quadratic trend 
C)  exponential trend 
D)  autoregressive(2)

Question 16

Carpet Outlet
A carpet outlet has been keeping daily sales records over the past four weeks as shown below.
 $$\begin{array}{l}
\text { Weat }\
\begin{array} { | l | c c c c | } 
\hline \text { Day } & 1 & 2 & 3 & 4 \
\hline \text { Manday } & 22 & 27 & 24 & 25 \
\text { Tuesday } & 25 & 29 & 25 & 27 \
\text { Wednesday } & 27 & 28 & 28 & 25 \
\text { Thursday } & 32 & 30 & 32 & 29 \
\text { Friday } & 35 & 32 & 34 & 33 \
\hline
\end{array}
\end{array}$$
-{Carpet Outlet Narrative} Calculate the daily indexes based on the regression trend line in the previous question.

Accepted Answer

The answer of Carpet Outlet
A carpet outlet has been keeping...

Question 17

Which of the following smoothing constants causes the most rapid reaction to a change in the current time series value?

Accepted Answer

A)  0.40 
B)  0.30 
C)  0.20 
D)  0.10

Question 18

Motor Oil Sales
As part of an effort to forecast future sales,the monthly motor oil sales (in thousands of gallons)for the past 10 months are recorded.These data are shown below.
 $$\begin{array} { | c | c | } 
\hline \text { Period } t & y _ { t } \
\hline 1 & 4 0 \
2 & 45 \
3 & 44 \
4 & 47 \
5 & 48 \
6 & 50 \
7 & 52 \
8 & 51 \
9 & 48 \
10 & 47 \
\hline
\end{array}$$
-{Motor Oil Sales Narrative} Draw the time series and the two sets of exponentially smoothed values.Does there appear to be a trend component in the time series?

Accepted Answer

The answer of Motor Oil Sales
As part of an effort...

Question 19

The trend equation for quarter sales data (in millions of dollars)for 2011-2015 is given by $\tilde { y } _ { t }$ = 6.8 + 1.2t,where t = 1 for the first quarter of 2011.The seasonal index for the third quarter of 2008 is 1.25.The forecasted sales' value for the third quarter of 2016 is:

Accepted Answer

A)  34.40 
B)  27.52 
C)  43.00 
D)  35.65

Question 20

Liquor Sales
The number of cases of liquor sold by a liquor wholesaler in an 8-year period follows.
 $$\begin{array} { l | l } 
2011 & 270 \
2012 & 356 \
2013 & 398 \
2014 & 456 \
2015 & 358 \
2016 & 500 \
2017 & 410 \
2018 & 376
\end{array}$$
-{Liquor Sales Narrative} A centered 5-year moving average is to be constructed for the liquor sales.The number of moving averages that will be calculated is ____________________.

Accepted Answer

The answer of Liquor Sales
The number of cases of liquor...

Exam 20: Time-Series Analysis and Forecasting

To create a seasonally adjusted time series,divide the time series by the seasonal ____________________.

In determining monthly seasonal indexes for natural gas consumption,the sum of the 12 means for gas consumption as a percentage of the moving average is 1195.To get the seasonal indexes,each monthly mean is to be multiplied by (1195 / 1200).

Forecasts based on trend and seasonality are generated by:

The number of four-period centered moving averages of a time series with 20 time periods is:

Smoothing time series data by the moving average method or exponential method is an attempt to dampen the effects of seasonal variation.

A time series is:

The mean absolute deviation averages the absolute differences between the actual values of the time series at time t and the forecast values at time:

The effect of an unpredictable,rare event will be contained in which component of the time series?

We compute the three-period moving averages for all time periods except the first and the last.

The most commonly used measures of forecast accuracy are ____________________ and the sum of squares for forecast errors (SSE).

Which of the following smoothing constants causes the most rapid reaction to a change in the current time series value?

The trend equation for quarter sales data (in millions of dollars) for 2011-2015 is given by $\tilde { y } _ { t }$ = 6.8 + 1.2t,where t = 1 for the first quarter of 2011.The seasonal index for the third quarter of 2008 is 1.25.The forecasted sales' value for the third quarter of 2016 is:

Exam 20: Time-Series Analysis and Forecasting

To create a seasonally adjusted time series,divide the time series by the seasonal ____________________.

In determining monthly seasonal indexes for natural gas consumption,the sum of the 12 means for gas consumption as a percentage of the moving average is 1195.To get the seasonal indexes,each monthly mean is to be multiplied by (1195 / 1200).

Forecasts based on trend and seasonality are generated by:

The number of four-period centered moving averages of a time series with 20 time periods is:

Smoothing time series data by the moving average method or exponential method is an attempt to dampen the effects of seasonal variation.

A time series is:

The mean absolute deviation averages the absolute differences between the actual values of the time series at time t and the forecast values at time:

The effect of an unpredictable,rare event will be contained in which component of the time series?

We compute the three-period moving averages for all time periods except the first and the last.

The most commonly used measures of forecast accuracy are ____________________ and the sum of squares for forecast errors (SSE).

Which of the following smoothing constants causes the most rapid reaction to a change in the current time series value?

The trend equation for quarter sales data (in millions of dollars) for 2011-2015 is given by y~t\tilde { y } _ { t }y~​t​ = 6.8 + 1.2t,where t = 1 for the first quarter of 2011.The seasonal index for the third quarter of 2008 is 1.25.The forecasted sales' value for the third quarter of 2016 is:

The trend equation for quarter sales data (in millions of dollars) for 2011-2015 is given by $\tilde { y } _ { t }$ = 6.8 + 1.2t,where t = 1 for the first quarter of 2011.The seasonal index for the third quarter of 2008 is 1.25.The forecasted sales' value for the third quarter of 2016 is: