Exam 16: Time-Series Forecasting

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 exponentially smoothed with a smoothing constant of 0.25.The forecast of the number of arrivals on the seventh Monday will be ________.

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 July?

TABLE 16-14 A contractor developed a multiplicative time-series model to forecast the number of contracts in future quarters,using quarterly data on number of contracts during the 3-year period from 2008 to 2010.The following is the resulting regression equation: ln Ŷ = 3.37 + 0.117 X - 0.083 Q₁ + 1.28 Q₂ + 0.617 Q₃ where Ŷ 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. Q₃ is a dummy variable equal to 1 in the third quarter of a year and 0 otherwise. -Referring to Table 16-14,using the regression equation,which of the following values is the best forecast for the number of contracts in the third quarter of 2011?

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 4-year period from 2005 to 2009.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 2005. 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. Q₃ is a dummy variable equal to 1 in the third quarter of a year and 0 otherwise. -Referring to Table 16-12,using the regression equation,what is the forecast for the revenues in the first quarter of 2012?

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 last smoothed value will be ________.

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 first month is 0: -Referring to Table 16-13,what is the p-value of the t test statistic for testing the appropriateness of the third-order autoregressive model?

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.

A second-order autoregressive model for average mortgage rate is: Rateᵢ = - 2.0 + 1.8(Rate)ᵢ₋₁ - 0.5 (Rate)ᵢ₋₂. If the average mortgage rate in 2010 was 7.0,and in 2009 was 6.4,the forecast for 2012 is ________.

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 4-year period from 2005 to 2009.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 2005. 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. Q₃ is a dummy variable equal to 1 in the third quarter of a year and 0 otherwise. -Referring to Table 16-12,the estimated quarterly compound growth rate in revenues is around

TABLE 16-8 The manager of a marketing consulting firm has been examining his company's yearly profits.He believes that these profits have been showing a quadratic trend since 1990.He uses Microsoft Excel to obtain the partial output below.The dependent variable is profit (in thousands of dollars),while the independent variables are coded years and squared of coded years,where 1990 is coded as 0,1991 is coded as 1,etc. -Referring to Table 16-8,the fitted value for 1990 is ________.

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 first month is 0: -Referring to Table 16-13,you can reject the null hypothesis for testing the appropriateness of the second-order autoregressive model at the 5% level of significance.

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,if this series is smoothed using exponential smoothing with a smoothing constant of 1/3,what would be the third value?

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 4-year period from 2005 to 2009.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 2005. 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. Q₃ 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 Q₂ (-0.054)in the regression equation is

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

Which of the following statements about moving averages is not true?

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,if a three-month moving average is used to smooth this series,what would be the second calculated value?

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

TABLE 16-10 -Referring to Table 16-10,the value of the MAD for the first-order autoregressive model is ________.

When a time series appears to be increasing at an increasing rate,such that percentage difference from value to value is constant,the appropriate model to fit is the

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