Exam 20: Time-Series Analytics and Forecasting

The fairly regular fluctuations that occur within each year would be contained in which component of the time series?

A time series for the years 1996-2001 is shown below. The forecasts for the years 2002-2004 with three smoothing constant values are: With w = .2,F₂₀₀₂ = F₂₀₀₃ = F₂₀₀₄ = 125.60 With w = .5,F₂₀₀₂ = F₂₀₀₃ = F₂₀₀₄ = 126.75 With w = .6,F₂₀₀₂ = F₂₀₀₃ = F₂₀₀₄ = 126.55 Compare each of the three sets of forecasts with the actual values for 2002-2004 given in the accompanying table,and compute the mean absolute deviation (MAD)for each model.Which model is best?

Seasonal variation is one of the four different components of a time series.These are cycles that occur over short repetitive calendar periods and,by definition,have duration of less than one year.

Motor Oil Sales As part of an effort to forecast future sales,the monthly motor oil sales (in thousands of gallons)for the past 10 months are recorded.These data are shown below. ​ ​ -{Motor Oil Sales Narrative} Apply exponential smoothing with w = 0.1 and w = 0.8 to help detect the components of the time series.

Smoothing time series data by the moving average method or exponential smoothing method is an attempt to remove the effect of the random variation component.

The seasonal variation,one of the four different components of a time series,is more likely to exhibit the relatively steady growth of the population of the United States from 181 million in 1960 to 273 million in 1999.

If data for a time series analysis are collected on a monthly basis only,which component of the time series may be ignored?

Which of the following smoothing constants causes the most rapid reaction to a change in the current time series value?

In measuring seasonal and random variation of a time series with no cyclical effect,we may use the:

Which of the following statements is false?

The easiest way of measuring the long-term trend is by regression analysis,where time is the dependent variable.

The mean absolute deviation is a measure of the average of the absolute discrepancies between the actual and the fitted values in a given time series.

Coffee Imports The coffee imports (in millions of dollars)from a Latin American country for 10 years are shown below. ​ ​ -{Coffee Imports Narrative} Plot the percentage of trend.

The time series component that reflects variability over short repetitive time periods and has duration of less than one year is called:

Quarterly Sales The quarterly sales (in millions of dollars)of a Motorcycle Dealership were recorded for the years 2011-2014.They are listed below. ​ ​ -{Quarterly Sales Narrative} Calculate the four-quarter centered moving averages.

One application of seasonal indexes is to remove the seasonal variation in a time series.The process is called ____________________,and the result is called a seasonally adjusted time series.

The effect of an unpredictable,rare event will be contained in which component of the time series?

In exponentially smoothed time series,the smoothing constant w is chosen on the basis of how much smoothing is required.In general,a small value of w such as 0.1 results in very little smoothing,while a large value of w such as 0.8 results in too much smoothing.

Biodiesel Sales Biodiesel (a vegetable oil or animal fat based diesel fuel)sales in Nebraska have been recorded over the past 10 months as shown below. ​ ​ -{Biodiesel Sales Narrative} Calculate the four-month moving average,and four-month centered moving average.

Liquor Sales The number of cases of liquor sold by a liquor wholesaler in an 8-year period follows. ​ ​ -{Liquor Sales Narrative} A centered 5-year moving average is to be constructed for the liquor sales.The moving average for 2016 is ____________________.