Exam 20: Time-Series Analysis and Forecasting

Which of the four-time series component is more likely to exhibit the changes in stock market prices at particular times during the course of one day?

One of the simplest ways to reduce random variation is to smooth the time series using moving averages and exponential smoothing.

The term "seasonal variation" may refer to:

Which of the following is not true in regard to the weights used in exponential smoothing?

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

Which of the following statements is false?

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. Month Jan. Feb. March April May June July Aug. Sept. Oct. Sales 75 72 81 92 90 105 112 107 110 93 -{Biodiesel Sales Narrative} Draw the time series and the two sets of exponentially smoothed values.Does there appear to be a trend component in the time series?

The model y_t = T_t * C_t*S_t * R_t that assumes the time series value at time t is the product of the four time series components is referred to as:

To measure the seasonal variation,we compute seasonal indexes,which gauge the degree to which the seasons differ from one another.

A time series for the years 2011-2016 is shown below. Year 2011 125 2012 115 2013 120 2014 126 2015 140 2016 122 Develop forecasts for the years 2002-2004,with the following smoothing constant values: w = 0.2,w = 0.5,and w = 0.6.

Hotel Occupancy A small hotel has recorded the number of rooms occupied during weekdays over a period of four weeks as is shown in the table below: Weat Day 1 2 3 4 Manday 16 15 18 21 Tue5day 22 21 20 25 Wednesday 20 23 20 24 Thursday 29 28 32 28 Friday 35 31 29 36 -{Hotel Occupancy Narrative} Find the regression trend line.

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

Quarterly enrollments in business statistics class for three years are shown in the table below.Compute the four-quarter centered moving averages. Year Quarter Enrollment 2011 1 26 2 29 3 33 4 18 2012 1 27 2 25 3 36 4 21 2013 1 32 2 36 3 39 4 30

If the time series is composed of seasonal variation and long-term trend,we can use seasonal indexes and the regression equation to forecast.

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

Liquor Sales The number of cases of liquor sold by a liquor wholesaler in an 8-year period follows. 2011 270 2012 356 2013 398 2014 456 2015 358 2016 500 2017 410 2018 376 -{Liquor Sales Narrative} Exponential smoothing with a weight or smoothing constant of 0.4 will be used to smooth the liquor sales.The smoothed value for 2015 is_________________.

The trend line $\hat { y }$ = 0.70 + 0.005t was calculated from quarterly data for 2000-2004,where t = 1 for the first quarter of 2000.The trend value for the second quarter of the year 2005 is:

Liquor Sales The number of cases of liquor sold by a liquor wholesaler in an 8-year period follows. 2011 270 2012 356 2013 398 2014 456 2015 358 2016 500 2017 410 2018 376 -{Liquor Sales Narrative} Exponential smoothing with a weight or smoothing constant of 0.2 will be used to smooth the liquor sales.The smoothed value for 2014 is_________________.

Holiday Hours The total holiday hours (in 1000s)were recorded for 16 quarters in a large steel mill as shown below. Year Quarter Overtime Hours 2011 1 32 2 15 3 21 4 28 2012 1 35 2 16 3 27 4 29 2013 1 36 2 21 3 25 4 37 2014 1 41 2 29 3 31 4 40 -{Holiday Hours Narrative} Use the regression technique to calculate the linear trend line.

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.