Exam 16: Time-Series Forecasting

TABLE 16-4 The number of cases of merlot wine sold by a Paso Robles winery in an 8-year period follows. -Referring to Table 16-4,construct a centered 3-year moving average for the wine sales.

The following is the list of MAD statistics for each of the models you have estimated from time-series data: Based on the MAD criterion,the most appropriate model is

TABLE 16-3 The following table contains the number of complaints received in a department store for the first 6 months of last year. -If you want to recover the trend using exponential smoothing,you will choose a weight (W)that falls in the range

TABLE 16-4 The number of cases of merlot wine sold by a Paso Robles winery in an 8-year period follows. -Referring to Table 16-4,exponential smoothing with a weight or smoothing constant of 0.2 will be used to forecast wine sales.The forecast for 2013 is ________.

TABLE 16-3 The following table contains the number of complaints received in a department store for the first 6 months of last year. -Referring to Table 16-3,suppose the last two smoothed values are 81 and 96 (Note: they are not).What would you forecast as the value of the time series for September?

True or False: Given a data set with 15 yearly observations,there are only seven 9-year moving averages.

TABLE 16-12 A local store developed a multiplicative time-series model to forecast its revenues in future quarters,using quarterly data on its revenues during the 5-year period from 2008 to 2012.The following is the resulting regression equation: log₁₀ = 6.102 + 0.012 X - 0.129 Q₁ - 0.054 Q₂ + 0.098 Q₃ where is the estimated number of contracts in a quarter X is the coded quarterly value with X = 0 in the first quarter of 2008 Q₁ is a dummy variable equal to 1 in the first quarter of a year and 0 otherwise Q₂ is a dummy variable equal to 1 in the second quarter of a year and 0 otherwise is a dummy variable equal to 1 in the third quarter of a year and 0 otherwise -Referring to Table 16-12,the best interpretation of the coefficient of X (0.012)in the regression equation is

TABLE 16-4 The number of cases of merlot wine sold by a Paso Robles winery in an 8-year period follows. -Referring to Table 16-4,a centered 5-year moving average is to be constructed for the wine sales.The moving average for 2010 is ________.

TABLE 16-5 The number of passengers arriving at San Francisco on the Amtrak cross-country express on 6 successive Mondays were: 60,72,96,84,36,and 48. -Referring to Table 16-5,the number of arrivals will be smoothed with a 5-term moving average.The first smoothed value will be ________.

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

A second-order autoregressive model for average mortgage rate is: Rate_i = -2.0 + 1.8 (Rate)_i-1 - 0.5 (Rate)_i-2. If the average mortgage rate in 2012 was 7.0,and in 2011 was 6.4,the forecast for 2014 is ________.

Which of the following terms describes the up and down movements of a time series that vary both in length and intensity?

TABLE 16-4 The number of cases of merlot wine sold by a Paso Robles winery in an 8-year period follows. -Referring to Table 16-4,construct a centered 5-year moving average for the wine sales.

True or False: Each forecast using the method of exponential smoothing depends on all the previous observations in the time series.

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

TABLE 16-6 The president of a chain of department stores believes that her stores' total sales have been showing a linear trend since 1993.She uses Microsoft Excel to obtain the partial output below.The dependent variable is sales (in millions of dollars),while the independent variable is coded years,where 1993 is coded as 0,1994 is coded as 1,etc. SUMMARY OUTPUT Regression Statistics Multiple R 0.604 R Square 0.365 Adjusted R Square 0.316 Standard Error 4.800 Observations 17 Coefficients Intercept 31.2 Coded Year 0.78 -Referring to Table 16-6,the forecast for sales (in millions of dollars)in 2013 is ________.

A model that can be used to make predictions about long-term future values of a time series is

TABLE 16-6 The president of a chain of department stores believes that her stores' total sales have been showing a linear trend since 1993.She uses Microsoft Excel to obtain the partial output below.The dependent variable is sales (in millions of dollars),while the independent variable is coded years,where 1993 is coded as 0,1994 is coded as 1,etc. SUMMARY OUTPUT Regression Statistics Multiple R 0.604 R Square 0.365 Adjusted R Square 0.316 Standard Error 4.800 Observations 17 Coefficients Intercept 31.2 Coded Year 0.78 -Referring to Table 16-6,the estimate of the amount by which sales (in millions of dollars)is increasing each year is ________.

TABLE 16-5 The number of passengers arriving at San Francisco on the Amtrak cross-country express on 6 successive Mondays were: 60,72,96,84,36,and 48. -Referring to Table 16-5,exponentially smooth the number of arrivals using a smoothing constant of 0.1.

TABLE 16-13 Given below is the monthly time-series data for U.S.retail sales of building materials over a specific year. The results of the linear trend,quadratic trend,exponential trend,first-order autoregressive,second-order autoregressive and third-order autoregressive model are presented below in which the coded month for the 1^st month is 0: Linear trend model: Quadratic trend model: Exponential trend model: First-order autoregressive: Second-order autoregressive: Third-order autoregressive: Below is the residual plot of the various models: -True or False: Referring to Table 16-13,the best model based on the residual plots is the second-order autoregressive model.