Exam 20: Time-Series Analytics and Forecasting

Mattress Sales Monthly mattress sales (in $1,000s)of a mattress store are shown below. ​ ​ -{Monthly Mattress Sales Narrative} Calculate the four-month moving average,and four-month centered moving average.

Given a data set with 15 yearly observations,there are only seven 9-year moving averages.

The trend line and seasonal indexes shown below were computed from four weeks of daily observations.Forecast the seven values for the next week. Trend Line: = 145 + 1.66t (t = 1,2,3,...28)

The most commonly used measures of forecast accuracy are mean absolute deviation (MAD)and the ____________________.

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. ​ ​ -The trend line = 0.75 + 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 0.86.

If there is no obvious trend or seasonality and we believe that there is a correlation between consecutive residuals,the ____________________ model may be most effective.

Which method would you recommend to your statistics professor in selecting the appropriate forecasting model if avoiding large errors is extremely important to him or her?

Daily Sandwich Sales The daily sales figures shown below have been recorded in a sandwich shop. ​ ​ -{Daily Sandwich Sales Narrative} Does there appear to be a seasonal (weekly)pattern?

The most commonly used measures of forecast accuracy are the mean absolute deviation (MAD)and the sum of squares for forecast error (SSE).

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

Which of the following statements about the method of exponential smoothing is not true?

A time series is shown in the table below: Compute the five-day moving averages to remove the seasonal and random variation.

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?

Photo Equipment Store Earnings The quarterly earnings of a chain of Photo Equipment stores have been recorded for the years 2011-2014.These data (in millions of dollars)are shown in the accompanying table. ​ ​ -{Photo Equipment Store Earnings Narrative} Forecast the quarterly earnings for the years 2015 and 2016.

The number of four-period centered moving averages of a time series with 20 time periods is:

Which of the following equations deseasonalize a time series,where T,C,S,and R are respectively the trend,cyclical,seasonal,and random variation components of the time series?

After estimating a trend model for annual time-series data,you obtain the following residual plot against time. The problem with your model is that:

We compute the five-period moving averages for all time periods except the first two and last two time periods.

A time series for the years 2011-2016 is shown below. 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: -{Hotel Occupancy Narrative} Calculate the seasonal (daily)indexes.