Question 1

If a forecast period is one month, then we will provide a new forecast each month.

Accepted Answer

A forecast period of one month implies that forecasts are updated and provided on a monthly basis to reflect the most current data and trends.

Question 2

One of the basic tools for creating a trend-based forecasting model is regression analysis.

Accepted Answer

Regression analysis is a statistical method used to estimate the relationships among variables, making it a fundamental tool for creating trend-based forecasting models by analyzing historical data to predict future trends.

Question 3

While virtually all time series exhibit a random component, not all time series exhibit other components.

Accepted Answer

Time series analysis often identifies several components such as trend, seasonal, and cyclical elements, but not all time series will have these components; however, the random (or irregular) component is generally present in all time series to some extent.

Question 4

A time-series graph shows that monthly income data have decreased gradually over the past 5 years. Given this, if a linear trend model is used to forecast future monthly income, the sign on the regression slope coefficient will be negative.

Accepted Answer

A linear trend model forecasting future monthly income based on a time-series graph showing a gradual decrease over the past 5 years would indeed have a negative slope coefficient, as the negative slope represents the decreasing trend in the data.

Question 5

Harrison Hollow, an upscale eatery in Atlanta, tracks its sales on a daily basis. Recently, the manager stated that sales over the past three weeks have been very cyclical. Given the data she has, this statement is not a reasonable one to make.

Accepted Answer

The statement is not reasonable because the data shows that sales have been increasing over the past three weeks, not cyclical.

Question 6

Some stocks are referred to as cyclical stock because they tend to be in favor for several years and then out of favor for several years. This is a correct use of the term cyclical.

Accepted Answer

Cyclical stocks are those whose performance is strongly tied to the economic cycle, showing higher returns during economic booms and lower returns in downturns, hence the pattern of being in and out of favor over several years.

Question 7

The Gilbert Company chief financial officer has been tracking annual sales for each of the company's three divisions for the past 10 years. At a recent meeting, he pointed to the annual data and indicated that it clearly showed the seasonality associated with its business. Given the data, this statement may have been very appropriate.

Accepted Answer

Seasonality refers to periodic fluctuations that regularly occur in a predictable pattern based on the season of the year, not annual sales data. Annual data would show year-over-year changes but not seasonal variations within each year.

Question 8

In order for a time series to exhibit a seasonal component, the data must be measured in periods as short or shorter than quarterly.

Accepted Answer

A seasonal component is a pattern that repeats over a period of one year or less. Quarterly data is measured in periods of three months, which is longer than one year. Therefore, quarterly data cannot exhibit a seasonal component.

Question 9

A stockbroker at a large brokerage firm recently analyzed the combined annual profits for all firms in the airline industry. One time-series component that may have been present in these annual data was a seasonal component.

Accepted Answer

Seasonal components are patterns that repeat over a specific period, such as quarters or months, within a year. The combined annual profits for all firms in the airline industry would not exhibit a seasonal component because seasonal variations are observed within a year, not from year to year.

Question 10

Two common unweighted indexes are the Paasche Index and the Laspeyres Index.

Accepted Answer

The Paasche Index and the Laspeyres Index are both weighted indexes, not unweighted. They use different weighting schemes to measure the changes in the price level of a basket of goods and services over time.

Question 11

If the historical data on which the model is being built consist of weekly data, the forecasting period would also be weekly.

Accepted Answer

The frequency of the historical data typically determines the frequency of the forecast, so weekly data would lead to weekly forecasts.

Question 12

If a manager is planning for an expansion of the factory, a forecast model with a long-term planning horizon would probably be used.

Accepted Answer

Long-term planning horizons are typically used for strategic decisions such as factory expansions, which require consideration of future demand, resources, and market conditions over several years.

Question 13

The time-series component that implies a long-term upward or downward pattern is called the trend component.

Accepted Answer

The trend component of a time series reflects long-term progression or decline, indicating an overall upward or downward direction in the data over time.

Question 14

Model specification is the process of determining how well a forecasting model fits the past data.

Accepted Answer

Model specification involves selecting the appropriate form of the model to represent the relationship between variables, not determining the fit of the model to past data.

Question 15

Stock analysts have recently stated in a meeting on Wall Street that over the past 50 years there have been periods of high market prices followed by periods of lower prices but over time prices have moved upwards. Given their statement, stock prices most likely exhibit only trend and cyclical components.

Accepted Answer

The statement implies that stock prices exhibit not only trend (long-term direction) and cyclical components (fluctuations due to economic cycles) but also potentially other components such as seasonal (regular fluctuations within a year) and irregular (unpredictable, random fluctuations) components, as the overall movement is not solely upward and involves fluctuations.

Question 16

An annual time series cannot exhibit a seasonal component.

Accepted Answer

An annual time series is a time series with a period of one year. A seasonal component is a component of a time series that repeats over a period of less than one year. Therefore, an annual time series cannot exhibit a seasonal component.

Question 17

The forecasting interval is the unit of time for which forecasts are made.

Accepted Answer

The forecasting interval refers to the range within which future values are expected to fall, with a certain probability, rather than the unit of time for which forecasts are made.

Question 18

In a recent meeting, a manager indicated that sales tend to be higher during October, November, and December and lower in the spring. In making this statement, she is indicating that sales for the company are cyclical.

Accepted Answer

The manager is indicating that sales are seasonal, not cyclical. Seasonal variations occur at the same time each year, while cyclical variations are related to economic cycles and do not follow a fixed pattern.

Question 19

To compare one value measured at one point in time with other values measured at different points in time, index numbers must be used.

Accepted Answer

Index numbers are specifically designed to compare values over different time periods by standardizing different data points, making it easier to see relative changes or differences over time.

Question 20

You are given the following linear trend model: Ft = 345.60 - 200.5(t). The forecast for period 15 is approximately -2,662.

Accepted Answer

The forecast for period 15 is calculated as Ft = 345.60 - 200.5(15) = -2,662.

Quiz 16: Analyzing and Forecasting Time-Series Data