Question 1

The forecast error is the difference between

Accepted Answer

A) this period's value and the next period's value 
B) the average value and the expected value of the response variable 
C) the explanatory variable value and the response variable value 
D) the actual value and the forecast 
A) this period's value and the next period's value 
B) the average value and the expected value of the response variable 
C) the explanatory variable value and the response variable value 
D) the actual value and the forecast

Question 2

The time series component that reflects a wavelike pattern describing a long-term trend that is generally apparent over a number of years is called cyclical.

Accepted Answer

A) True 
 B)False

Question 3

(A)Perform a runs test and compute a few autocorrelations to determine whether this time series is random.
(B)Obtain a time series chart.Which of the exponential smoothing models do you think should be used for forecasting based on this chart? Why?
(C)Use simple exponential smoothing to forecast these data,using no holdout period and requesting 4 quarters of future forecasts.Use the default smoothing constant of 0.10.
(D)Repeat (C),optimizing the smoothing constant.Does it make much of an improvement?

Accepted Answer

(A) @#IMG-DLM& There is almost no evidence of nonr

Question 4

The runs test is a formal test of the null hypothesis of randomness.If there are too many or too few runs in the series,then we conclude that the series is not random.

Accepted Answer

A) True 
 B)False

Question 5

(A)At the beginning of May,what is the forecast of July's wine sales?
(B)Suppose that actual demands during May and June are as follows: May,5000 bottle of wine; June 4000 bottle of wine.After observing June's demand,what is the forecast for July's demand?
(C)Based on the data from (B),the demands during May and June average (5000+4000)/2 = 4500 bottle per month.This is the same as the forecast for monthly sales before we observed the May and June data.Yet after we observe the May and June demands for wine,our forecast for July demand has decreased from what it was at the end of April.Why?

Accepted Answer

(A)Forecast for July is 4500 bottles.(B)

Question 6

Correlogram is a bar chart of autocorrelation at different lags.

Accepted Answer

A) True 
 B)False

Question 7

The smoothing constant used in simple exponential smoothing is analogous to the span in moving averages.

Accepted Answer

A) True 
 B)False

Question 8

In a random series,successive observations are probabilistically independent of one another.If this property is violated,the observations are said to be:

Accepted Answer

A) autocorrelated 
B) intercorrelated 
C) causal 
D) seasonal 
A) autocorrelated 
B) intercorrelated 
C) causal 
D) seasonal

Question 9

An equation for the random walk model is given by the equation:   ,where   is the change in the time series from time t to time t - 1,   is a constant,and   is a random variable (noise)with mean 0 and some standard deviation   .

Accepted Answer

A) True 
 B)False

Question 10

A shortcoming of the RMSE (root mean square error)is that it is not in the same units as the forecast variable.

Accepted Answer

A) True 
 B)False

Question 11

The most common form of autocorrelation is positive autocorrelation,in which:

Accepted Answer

A) large observations tend to follow both large and small observations 
B) small observations tend to follow both large and small observations 
C) large observations tend to follow large observations and small observations tend to follow small observations 
D) large observations tend to follow small observations and small observations tend to follow large observations 
A) large observations tend to follow both large and small observations 
B) small observations tend to follow both large and small observations 
C) large observations tend to follow large observations and small observations tend to follow small observations 
D) large observations tend to follow small observations and small observations tend to follow large observations

Question 12

At the beginning of April,what is the forecast of June's Pepsi sales?

Accepted Answer

Forecast f

Question 13

The purpose of using the moving average is to take away the short-term seasonal and random variation,leaving behind a combined trend and cyclical movement.

Accepted Answer

A) True 
 B)False

Question 14

The linear trend   was estimated using a time series with 20 time periods.The forecasted value for time period 21 is

Accepted Answer

A) 120 
B) 122 
C) 160 
D) 162 
A) 120 
B) 122 
C) 160 
D) 162

Question 15

Suppose that a simple exponential smoothing model is used (with   = 0.40)to forecast monthly sandwich sales at a local sandwich shop.The forecasted demand for September was 1560 and the actual demand was 1480 sandwiches.Given this information,what would be the forecast number of sandwiches for October?

Accepted Answer

A) 1480 
B) 1528 
C) 1560 
D) 1592 
A) 1480 
B) 1528 
C) 1560 
D) 1592

Question 16

When using the moving average method,you must select _____which represent(s)the number of terms in the moving average.

Accepted Answer

A) a smoothing constant 
B) the explanatory variables 
C) an alpha value 
D) a span 
A) a smoothing constant 
B) the explanatory variables 
C) an alpha value 
D) a span

Question 17

The components of a time series include:

Accepted Answer

A) base series 
B) trend 
C) seasonal component 
D) cyclic component 
E) all of these options 
A) base series 
B) trend 
C) seasonal component 
D) cyclic component 
E) all of these options

Question 18

When using Holt's model,choosing values of the smoothing constant   that are near 1 will result in forecast models which

Accepted Answer

A) react very quickly to changes in the level 
B) react very quickly to changes in the trend 
C) react very quickly to changes in the level and the trend 
D) react very slowly to changes in the level and the trend 
A) react very quickly to changes in the level 
B) react very quickly to changes in the trend 
C) react very quickly to changes in the level and the trend 
D) react very slowly to changes in the level and the trend

Question 19

Develop a time series plot of the data.Does the data appear random on the plot?

Accepted Answer

@#IMG-DLM& The data definitely

Question 20

Use the method of moving averages with an appropriate span to forecast retail sales for the first half of 2009.Do you obtain a good fit? Do you have confidence in your forecast? Explain your answers.

Accepted Answer

@#IMG-DLM& @#IMG-DLM& The fit statistics show a MA

The forecast error is the difference between

The time series component that reflects a wavelike pattern describing a long-term trend that is generally apparent over a number of years is called cyclical.

The runs test is a formal test of the null hypothesis of randomness.If there are too many or too few runs in the series,then we conclude that the series is not random.

Correlogram is a bar chart of autocorrelation at different lags.

The smoothing constant used in simple exponential smoothing is analogous to the span in moving averages.

In a random series,successive observations are probabilistically independent of one another.If this property is violated,the observations are said to be:

An equation for the random walk model is given by the equation: ,where is the change in the time series from time t to time t - 1, is a constant,and is a random variable (noise)with mean 0 and some standard deviation .

A shortcoming of the RMSE (root mean square error)is that it is not in the same units as the forecast variable.

The most common form of autocorrelation is positive autocorrelation,in which:

At the beginning of April,what is the forecast of June's Pepsi sales?

The purpose of using the moving average is to take away the short-term seasonal and random variation,leaving behind a combined trend and cyclical movement.

The linear trend was estimated using a time series with 20 time periods.The forecasted value for time period 21 is

When using the moving average method,you must select _____which represent(s)the number of terms in the moving average.

The components of a time series include:

When using Holt's model,choosing values of the smoothing constant that are near 1 will result in forecast models which

Develop a time series plot of the data.Does the data appear random on the plot?

Use the method of moving averages with an appropriate span to forecast retail sales for the first half of 2009.Do you obtain a good fit? Do you have confidence in your forecast? Explain your answers.

Introduction to Data Analysis and Decision Making

Describing the Distribution of a Single Variable

Finding Relationships Among Variables

Probability and Probability Distributions

Normal, binomial, poisson, and Exponential Distributions

Decision Making Under Uncertainty

Sampling and Sampling Distributions

Confidence Interval Estimation

Hypothesis Testing

Regression Analysis: Estimating Relationships

Regression Analysis: Statistical Inference

Introduction to Optimization Modeling

Optimization Modeling: Applications

Introduction to Simulation Modeling

Simulation Models

Filters

Exam 12: Time Series Analysis and Forecasting

The forecast error is the difference between

The time series component that reflects a wavelike pattern describing a long-term trend that is generally apparent over a number of years is called cyclical.

The runs test is a formal test of the null hypothesis of randomness.If there are too many or too few runs in the series,then we conclude that the series is not random.

Correlogram is a bar chart of autocorrelation at different lags.

The smoothing constant used in simple exponential smoothing is analogous to the span in moving averages.

In a random series,successive observations are probabilistically independent of one another.If this property is violated,the observations are said to be:

An equation for the random walk model is given by the equation: ,where is the change in the time series from time t to time t - 1, is a constant,and is a random variable (noise)with mean 0 and some standard deviation .

A shortcoming of the RMSE (root mean square error)is that it is not in the same units as the forecast variable.

The most common form of autocorrelation is positive autocorrelation,in which:

At the beginning of April,what is the forecast of June's Pepsi sales?

The purpose of using the moving average is to take away the short-term seasonal and random variation,leaving behind a combined trend and cyclical movement.

The linear trend was estimated using a time series with 20 time periods.The forecasted value for time period 21 is

When using the moving average method,you must select _____which represent(s)the number of terms in the moving average.

The components of a time series include:

When using Holt's model,choosing values of the smoothing constant that are near 1 will result in forecast models which

Develop a time series plot of the data.Does the data appear random on the plot?

Use the method of moving averages with an appropriate span to forecast retail sales for the first half of 2009.Do you obtain a good fit? Do you have confidence in your forecast? Explain your answers.

Introduction to Data Analysis and Decision Making

Describing the Distribution of a Single Variable

Finding Relationships Among Variables

Probability and Probability Distributions

Normal, binomial, poisson, and Exponential Distributions

Decision Making Under Uncertainty

Sampling and Sampling Distributions

Confidence Interval Estimation

Hypothesis Testing

Regression Analysis: Estimating Relationships

Regression Analysis: Statistical Inference

Introduction to Optimization Modeling

Optimization Modeling: Applications

Introduction to Simulation Modeling

Simulation Models

Filters