Exam 18: Models for Time Series and Forecasting

In the classical time series model,the time series is made up of (T),(C),(S),and (I)components What do these initials indicate?

Stock exchange Membership on a stock exchange for five years is given below: Year Members 1996 520 1997 510 1998 505 1999 508 2000 512 -Use the exponential smoothing procedure to obtain estimates of the trend.Set the smoothed value for 1996 equal to the actual and use a smoothing constant, $\alpha$ = 0.2.Compute the forecasted value for 2000.

The mean absolute deviation averages the absolute differences between the actual values of the time series at time t and the forecast values at time:

A common method of testing for autocollinearity (serial correlation)is a Wilcoxon signed rank test for one sample.

Selecting a small value for the smoothing constant ( $\alpha$ )in exponential smoothing results in

Of the four components of the multiplicative time series model,the ratio-to-moving average procedure isolates the:

Table - 5 -8 3 2 4 6 -9 3 -5 -2 -0.4 3 10 0.3 - 16 18 21 -4 -2 10 13 -20 -8 15 19 -8 -6 -1 -At the 0.01 significance level with n = 15,k = 2,test the hypothesis that there is positive autocorrelation present.What is the appropriate conclusion?

In 2000 a company's inventory costs were $4 million.Then the index number for the 2000 base period is ____________________.

Based on annual car rentals over years,a rental firm has developed the following quadratic trend equation: $\hat { Y }$ = 425 + 18x + 6.5x²,with x = 1 for 1998.Forecast y for 2005.

The following seasonal indexes and linear trend were computed from five year quarterly sales data. Trend line is $\hat { y } = 500 + 30 t , ( t = 1,2,3 , \ldots .20 )$ Quarter Sea50nal Index 1 1.4 2 1.2 3 0.9 4 0.5 Forecast the sales for the next four quarters

For each of the following,indicate which time series component is represented.Explain your reasoning. A)The Dean of a Business College finds Monday is the most popular day of the week for professors' absence.Explain: B) Political advertising in the United States peaks every 4 years. Explain: C) Sales of a blood pressure medication decline after the product receives negative publicity in a medical journal article. Explain:

A factor that inflates or deflates a trend value to compensate for the effect of a pattern that repeats over a period of one year or less is known as a

The trend component of a time series can be examined (1)by using regression techniques to fit a trend line to the data,or (2)by using smoothing techniques to moderate the peaks and valleys within the series.

The component of a time series that has repeating patterns that have a period longer than one year is the:

In determining monthly seasonal indexes for electrical consumption,the sum of the 12 means for electrical consumption as a percentage of the moving average is 1193.To get the seasonal indexes,each monthly mean is to be multiplied by ________________________.

According to the chapter,regression models based on time series data are especially susceptible to autocorrelation.Why?

Why is it desirable to shift the base of an index?

Highland Automotvie The table below summarizes the number of new cars Highland Automotive sold during each of the last five weeks along with a forecast that was generated for each of those weeks. Week Number af Cars 5ald Farecast 1 24 20 2 21 22 3 25 21 4 19 23 5 34 21 -What is the mean squared error for this forecast?

The Mean Absolute Deviation criterion is analogous to the least squares criterion used in determining the regression equation.

The trend equation for annual sales is $\hat { Y }$ = 32 + 3.1x where x = 0 in 1992.Sales (y)are in millions of dollars.The monthly seasonal index for July is 98.What is the July sales estimate for 2000?