Exam 16: Time-Series Forecasting

SCENARIO 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 2009 to 2013.The following is the resulting regression equation: 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. is a dummy variable equal to 1 in the first quarter of a year and 0 otherwise. 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 Scenario 16-12, in testing the significance of the coefficient of X in the regression equation (0.012)which has a p-value of 0.0000.Which of the following is the best interpretation of this result?

SCENARIO 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 2011 to 2013.The following is the resulting regression equation: where is the estimated number of contracts in a quarter. X is the coded quarterly value with X = 0 in the first quarter of 2011. is a dummy variable equal to 1 in the first quarter of a year and 0 otherwise. Q 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 Scenario 16-14, to obtain a forecast for the fourth quarter of 2014 using the model, which of the following sets of values should be used in the regression equation?

If you want to recover the trend using exponential smoothing, you will choose a weight (W)that falls in the range

A first-order autoregressive model for stock sales is: Salesi = 800 + 1.2(Sales)i-1. If sales in 2012 is 6,000, the forecast of sales for 2013 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

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

In selecting an appropriate forecasting model, the following approaches are suggested:

SCENARIO 16-7 The executive vice-president of a drug manufacturing firm believes that the demand for the firm's most popular drug has been evidencing an exponential trend since 1999.She uses Microsoft Excel to obtain the partial output below.The dependent variable is the log base 10 of the demand for the drug, while the independent variable is years, where 1999 is coded as 0, 2000 is coded as 1, etc. SUMMARY OUTPUT -Referring to Scenario 16-7, the fitted trend value for 2004 is __________.

SCENARIO 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 month is 0: Below is the residual plot of the various models: -Referring to Scenario 16-13, what is the exponentially smoothed value for the first month using a smoothing coefficient of W = 0.25?

SCENARIO 16-4 The number of cases of merlot wine sold by a Paso Robles winery in an 8-year period follows. -Referring to Scenario 16-4, exponential smoothing with a weight or smoothing constant of 0.2 will be used to smooth the wine sales.The value of E4, the smoothed value for 2008 is __________.

SCENARIO 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 Scenario 16-5, the number of arrivals will be exponentially smoothed with a smoothing constant of 0.1.The smoothed value for the second Monday will be __________.

SCENARIO 16-9 Given below are EXCEL outputs for various estimated autoregressive models for a company's real operating revenues (in billions of dollars)from 1989 to 2012.From the data, you also know that the real operating revenues for 2010, 2011, and 2012 are 11.7909, 11.7757 and 11.5537, respectively. -Referring to Scenario 16-9, if one decides to use the Third-Order Autoregressive model, what will the predicted real operating revenue for the company be in 2015?

SCENARIO 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 Scenario 16-3, if a three-month moving average is used to smooth this series, what would be the second calculated value?

SCENARIO 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 2009 to 2013.The following is the resulting regression equation: 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. is a dummy variable equal to 1 in the first quarter of a year and 0 otherwise. 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 Scenario 16-12, in testing the significance of the coefficient for in the regression equation (- 0.129)which has a p-value of 0.492.Which of the following is the best interpretation of this result?

SCENARIO 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 2011 to 2013.The following is the resulting regression equation: where is the estimated number of contracts in a quarter. X is the coded quarterly value with X = 0 in the first quarter of 2011. is a dummy variable equal to 1 in the first quarter of a year and 0 otherwise. Q 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 Scenario 16-14, in testing the coefficient for in the regression equation (- 0.083), the results were a t-statistic of - 0.66 and an associated p-value of 0.530.Which of the following is the best interpretation of this result?

SCENARIO 16-1 The number of cases of chardonnay wine sold by a Paso Robles winery in an 8-year period follows: -Referring to Scenario 16-1, does there appear to be a relationship between year and the number of cases of wine sold?

SCENARIO 16-11 The manager of a health club has recorded mean attendance in newly introduced step classes over the last 15 months: 32.1, 39.5, 40.3, 46.0, 65.2, 73.1, 83.7, 106.8, 118.0, 133.1, 163.3, 182.8, 205.6, 249.1, and 263.5.She then used Microsoft Excel to obtain the following partial output for both a first- and second-order autoregressive model. SUMMARY OUTPUT - Order Model SUMMARY OUTPUT - 1 Order Model -Referring to Scenario 16-11, using the second-order model, the forecast of mean attendance for month 17 is __________.

SCENARIO 16-7 The executive vice-president of a drug manufacturing firm believes that the demand for the firm's most popular drug has been evidencing an exponential trend since 1999.She uses Microsoft Excel to obtain the partial output below.The dependent variable is the log base 10 of the demand for the drug, while the independent variable is years, where 1999 is coded as 0, 2000 is coded as 1, etc. SUMMARY OUTPUT -Referring to Scenario 16-7, the forecast for the demand in 2016 is __________.

The method of moving averages is used

SCENARIO 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 Scenario 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 __________.