Exam 18: Time Series and Forecasting

Prices of crude oil have been steadily rising over the last two years (The Wall Street Journal, December 14, 2010). The monthly data on price per gallon of unleaded regular gasoline in the United States from January 2009 to December 2010 were available. Three trend models were created starting with t = 1 and the following output was generated. Which of the following is a cubic trend equation used to forecast for the price of regular unleaded gasoline?

Which of the following is a similarity between the exponential smoothing method and the moving average method?

A linear trend can be estimated using ________ technique.

Quarterly sales of a department store for the last seven years are given in the following table. The scatterplot shows that the quarterly sales have an increasing trend and seasonality. A linear regression model Sales = β₀ + β₁Qtr1 + β₂Qtr2 + β₃Qtr3 + β₄t + ε, with dummy variables Qtr1, Qtr2, and Qtr3, is used to make forecasts. For the regression model, the following partial output is available. What is the regression equation for the linear trend model with seasonal dummy variables?

If the model y_t = T_t × S_t × I_t is applied, which of the following indicates no seasonality?