Question 1

Which of the following will be reflected by deseasonalized time series?

Accepted Answer

A)  Trend effects 
B)  Cyclical effects 
C)  Random variation 
D)  All of these choices are true. 
A)  Trend effects 
B)  Cyclical effects 
C)  Random variation 
D)  All of these choices are true.

Question 2

If we have 5 years of monthly observations,we may use the first four years to develop several competing forecasting models,and then use them to forecast the fifth year.Since we know the actual values in the fifth year,we can choose the technique that results in the most accurate forecast using either the mean absolute deviation (MAD)or the sum of squares for forecast error (SSE).

Accepted Answer

A) True 
 B)False

Question 3

After estimating a trend model for annual time-series data,you obtain the following residual plot against time.   The problem with your model is that:

Accepted Answer

A)  the cyclical component has not been accounted for 
B)  the seasonal component has not been accounted for 
C)  the trend component has not been accounted for 
D)  the irregular component has not been accounted for 
A)  the cyclical component has not been accounted for 
B)  the seasonal component has not been accounted for 
C)  the trend component has not been accounted for 
D)  the irregular component has not been accounted for

Question 4

A time series is shown in the table below:
 $$\begin{array}{l}
\quad\quad\quad\quad\quad\quad\quad\quad\text { Week }\
\begin{array} { | l | c c c c } 
\hline \text { Day } & 1 & 2 & 3 & 4 \
\hline \text { Manday } & 16 & 15 & 18 & 21 \
\text { Tuesday } & 22 & 21 & 20 & 25 \
\text { Wednesday } & 20 & 23 & 20 & 24 \
\text { Thursday } & 29 & 28 & 32 & 28 \
\text { Friday } & 35 & 31 & 29 & 36 \
\hline
\end{array}
\end{array}$$ Compute the five-day moving averages to remove the seasonal and random variation.

Accepted Answer

\[\begin{array} { | c | c c | } 
\hline

Question 5

A least squares ____________________ trend line is just a simple regression line with the years recoded.

Accepted Answer

The answer of A least squares ____________________ trend line is...

Question 6

Which of the following is not an advantage of exponential smoothing?

Accepted Answer

A)  It enables us to perform on-period ahead forecasting 
B)  It enables us to perform more than one-period ahead forecasting 
C)  It enables us to smooth out seasonal components 
D)  It enables us to smooth out cyclical components 
A)  It enables us to perform on-period ahead forecasting 
B)  It enables us to perform more than one-period ahead forecasting 
C)  It enables us to smooth out seasonal components 
D)  It enables us to smooth out cyclical components

Question 7

A time series for the years 1996-2001 is shown below.
 $$\begin{array} { | c | c | } 
\hline \text { Year } & y _ { \mathbf { t } } \
\hline 1996 & 125 \
1997 & 115 \
1998 & 120 \
1999 & 126 \
2000 & 140 \
2001 & 122 \
\hline
\end{array}$$ The forecasts for the years 2002-2004 with three smoothing constant values are:
With w = .2,F2002 = F2003 = F2004 = 125.60
With w = .5,F2002 = F2003 = F2004 = 126.75
With w = .6,F2002 = F2003 = F2004 = 126.55
Compare each of the three sets of forecasts with the actual values for 2002-2004 given in the accompanying table,and compute the mean absolute deviation (MAD)for each model.Which model is best?
 $$\begin{array} { | c | c | } 
\hline \text { Year } & y _ { \mathbf { t } } \
\hline 2002 & 130 \
2003 & 125 \
2004 & 135 \
\hline
\end{array}$$

Accepted Answer

@#LAT-DLM& With w = 0.2,MAD = 4.80.With

Question 8

If we want to measure the seasonal variations on stock market performance by month,we would need:

Accepted Answer

A)  50 indicator variables since the stock market has a 5-day work per week 
B)  12 indicator variables to represent the 12 months 
C)  11 indicator variables 
D)  52 indicator variables 
A)  50 indicator variables since the stock market has a 5-day work per week 
B)  12 indicator variables to represent the 12 months 
C)  11 indicator variables 
D)  52 indicator variables

Question 9

The regression trend line for annual energy consumption for 2000-2020 is given by $\tilde { y } _ { t }$ = 70 + 0.50t,where t = 1 for 2000.If the annual energy consumption for 2015 was 72.5,then the percentage of trend for 2015 was:

Accepted Answer

A)  93.548 
B)  106.897 
C)  92.949 
D)  107.586 
A)  93.548 
B)  106.897 
C)  92.949 
D)  107.586

Question 10

Microprocessors
Annual production (in millions)of computer microprocessors in a large electronics company was recorded as shown below
 $$\begin{array} { | c | r c | } 
\hline \text { Year } & t & \text { Production } \
\hline 2011 & 1 & 26 \
2012 & 2 & 23 \
2013 & 3 & 21 \
2014 & 4 & 25 \
2015 & 5 & 32 \
2016 & 6 & 38 \
2017 & 7 & 43 \
2018 & 8 & 36 \
2019 & 9 & 29 \
2020 & 10 & 25 \
\hline
\end{array}$$
-{Microprocessors Narrative} Describe the cyclical effect (if there is one).

Accepted Answer

There appears to be

Question 11

The mean absolute deviation is the summation of the residuals divided by the sample size.

Accepted Answer

A) True 
 B)False

Question 12

Daily Hoagie Sales
The table below shows the number of hoagies sold daily during a four-week period at Hoagie Haven in Sutton,West Virginia.
 $$\begin{array}{l}
\quad\quad\quad\quad\quad\quad\quad\quad\text { Week }\
\begin{array} { | l | c c c c | } 
\hline \text { Day } & 1 & 2 & 3 & 4 \
\hline \text { Sunday } & 253 & 234 & 248 & 232 \
\text { Monday } & 98 & 93 & 99 & 104 \
\text { Tuesday } & 106 & 88 & 87 & 115 \
\text { Wednesday } & 119 & 134 & 113 & 102 \
\text { Thursday } & 138 & 123 & 130 & 118 \
\text { Friday } & 201 & 215 & 218 & 205 \
\text { Saturday } & 327 & 399 & 415 & 390 \
\hline
\end{array}
\end{array}$$
-{Daily Hoagie Sales Narrative} Calculate the seasonal (daily)indexes,using a seven-day moving average.

Accepted Answer

The answer of Daily Hoagie Sales
The table below shows the...

Question 13

Biodiesel Sales
Biodiesel (a vegetable oil or animal fat based diesel fuel)sales in Nebraska have been recorded over the past 10 months as shown below.
 $\begin{array}{l|llllllllll}
\text { Month } & \text { Jan. } & \text { Feb. } & \text { March } & \text { April } & \text { May } & \text { June } & \text { July } & \text { Aug. } & \text { Sept. } & \text { Oct. } \
\hline \text { Sales } & 75 & 72 & 81 & 92 & 90 & 105 & 112 & 107 & 110 & 93
\end{array}$

-{Biodiesel Sales Narrative} Compute the five-month moving average.

Accepted Answer

\[\begin{array} { l | c c } 
\text { Mon

Question 14

The way a seasonal index is computed involves which of the following steps?

Accepted Answer

A)  Remove the effect of seasonal and random variation by regression analysis. 
B)  For each time period,compute the ratio,which removes most of the trend variation for that time period. 
C)  Calculate the average of all the ratios:over all time periods to remove random variation and leaving a measure of seasonality. 
D)  All of these choices are true. 
A)  Remove the effect of seasonal and random variation by regression analysis. 
B)  For each time period,compute the ratio,which removes most of the trend variation for that time period. 
C)  Calculate the average of all the ratios:over all time periods to remove random variation and leaving a measure of seasonality. 
D)  All of these choices are true.

Question 15

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} Exponential smoothing with a weight or smoothing constant of 0.4 will be used to smooth the liquor sales.The smoothed value for 2012 is_________________.

Accepted Answer

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

Question 16

The term "seasonal variation" may refer to the four traditional seasons,or to systematic patterns that occur during a month,a week,or even one day.

Accepted Answer

A) True 
 B)False

Question 17

We calculate the three-period moving average for a time series for all time periods except the first period.

Accepted Answer

A) True 
 B)False

Question 18

The method of least squares is used on time-series data for

Accepted Answer

A)  eliminating irregular movements 
B)  deseasonalizing the data 
C)  obtaining the trend equation 
D)  exponentially smoothing a series 
A)  eliminating irregular movements 
B)  deseasonalizing the data 
C)  obtaining the trend equation 
D)  exponentially smoothing a series

Question 19

The equation: St = w .yt + (1- w).St  -  1 (for t $\ge$2)refers to exponentially smoothed time series.

Accepted Answer

A) True 
 B)False

Question 20

Based on the following scatter plot,which of the time-series components is not present in this quarterly time series?

Accepted Answer

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

Exam 20: Time-Series Analysis and Forecasting

Which of the following will be reflected by deseasonalized time series?

After estimating a trend model for annual time-series data,you obtain the following residual plot against time. The problem with your model is that:

A time series is shown in the table below: Week Day 1 2 3 4 Manday 16 15 18 21 Tuesday 22 21 20 25 Wednesday 20 23 20 24 Thursday 29 28 32 28 Friday 35 31 29 36 Compute the five-day moving averages to remove the seasonal and random variation.

A least squares ____________________ trend line is just a simple regression line with the years recoded.

Which of the following is not an advantage of exponential smoothing?

If we want to measure the seasonal variations on stock market performance by month,we would need:

The regression trend line for annual energy consumption for 2000-2020 is given by y~t\tilde { y } _ { t }y~​t​ = 70 + 0.50t,where t = 1 for 2000.If the annual energy consumption for 2015 was 72.5,then the percentage of trend for 2015 was:

The mean absolute deviation is the summation of the residuals divided by the sample size.

The way a seasonal index is computed involves which of the following steps?

The term "seasonal variation" may refer to the four traditional seasons,or to systematic patterns that occur during a month,a week,or even one day.

We calculate the three-period moving average for a time series for all time periods except the first period.

The method of least squares is used on time-series data for

The equation: St = w .yt + (1- w).St - 1 (for t ≥\ge≥ 2)refers to exponentially smoothed time series.

Based on the following scatter plot,which of the time-series components is not present in this quarterly time series?

What Is Statistics

Graphical Descriptive Techniques I

Graphical Descriptive Techniques II

A: Numerical Descriptive Techniques

B: Numerical Descriptive Techniques

C: Numerical Descriptive Techniques

Data Collection and Sampling

Probability

A: Random Variables and Discrete Probability Distributions

B: Random Variables and Discrete Probability Distributions

Continuous Probability Distributions

Sampling Distributions

Introduction to Estimation

Introduction to Hypothesis Testing

Inference About a Population

Inference About Comparing Two Populations

Analysis of Variance

Chi-Squared Tests

A: Simple Linear Regression and Correlation

B: Simple Linear Regression and Correlation

Multiple Regression

Model Building

Nonparametric Statistics

Statistical Process Control

Decision Analysis

Conclusion

Filters

The regression trend line for annual energy consumption for 2000-2020 is given by $\tilde { y } _ { t }$ = 70 + 0.50t,where t = 1 for 2000.If the annual energy consumption for 2015 was 72.5,then the percentage of trend for 2015 was:

The equation: S_t = w .y_t + (1- w).S_t _- ₁ (for t $\ge$ 2)refers to exponentially smoothed time series.