Exam 18: Time Series and Forecasting

A polynomial trend model that only allows one change in the direction of a series is known as a(n)_______.

If the regression framework is used to describe monthly seasonal data,how many dummy variables are needed?

Which of the following is not a criticism made of qualitative forecasts?

In the decomposition method,which of the following time series are not used to estimate the trend?

The following table shows the annual revenues (in millions of dollars)of a pharmaceutical company over the period 1990-2011. The autoregressive models of order 1 and 2,y_t = β₀ + β₁y_{t - 1} + ε_t,and y_t = β₀ + β₁y_{t - 1} + β₂y_{t - 2}+ ε_t,were applied on the time series to make revenue forecasts.The relevant parts of Excel regression outputs are given below. Model AR(1): Model AR(2): Using the AR(2)model,find the company revenue forecast for 2012.

The centered moving average (CMA),applied in the decomposition analysis of a time series with trend and seasonality,is the average of two consecutive moving averages.

The exponential trend model is attractive when the increase in the series gets larger over time.

The following table shows the annual revenues (in millions of dollars)of a pharmaceutical company over the period 1990-2011. The Excel scatterplot shown indicates that the annual revenues have an increasing trend.Therefore,linear,exponential,quadratic,and cubic models were used to fit the trend,and the following relevant information became available after applying linear regression. When three polynomial trend equations are compared,which of them provides the best fit?

Which of the following formulas is used to make forecasts using the exponential trend model?

The ________ method is a smoothing technique based on computing the average from a fixed number of the most recent observations.

The following table shows the annual revenues (in millions of dollars)of a pharmaceutical company over the period 1990-2011. The autoregressive models of order 1 and 2,y_t = β₀ + β₁y_{t - 1} + ε_t,and y_t = β₀ + β₁y_{t - 1} + β₂y_{t - 2} + ε_t,were applied on the time series to make revenue forecasts.The relevant parts of Excel regression outputs are given below. Model AR(1): Model AR(2): Compare Excel outputs for AR(1)and AR(2)and choose the forecasting model that seems to be better.

The following table includes the information about a monthly time series. When the exponential smoothing method with α = 0.1 is applied,what is the MSE?

The following table includes the information about a monthly time series. When the exponential smoothing method with α = 0.1 is applied,what is the MAD?

Which of the following types of trend models will best suit a series where the value of the series changes by a fixed amount for each period?

The following table includes the information about a monthly time series. When the exponential smoothing method with α = 0.5 is applied,what is the MSE?

The ________ is a trend model that allows for one change in the direction of a series.

The following table shows the annual revenues (in millions of dollars)of a pharmaceutical company over the period 1990-2011. The Excel scatterplot shown indicates that the annual revenues have an increasing trend.Therefore,linear,exponential,quadratic,and cubic models were used to fit the trend,and the following relevant information became available after applying linear regression. Which of the following is the revenue forecast for 2012 found by the linear trend equation?

The regression y_t = β₀ + β₁y_t-1 + ε_t is referred to as a(n)____________ model of order one.

In the time series decomposition method,to obtain the _______,we divide the original observations by their corresponding adjusted seasonal indices.

The following table shows the annual revenues (in millions of dollars)of a pharmaceutical company over the period 1990-2011. The Excel scatterplot shown indicates that the annual revenues have an increasing trend.Therefore,linear,exponential,quadratic,and cubic models were used to fit the trend,and the following relevant information became available after applying linear regression. Using the linear trend equation,one can say that the predicted revenue increases by ____________.