Time Series Analysis Test 1 — Questions and Answers
Question 1: The graph of a time series is referred to as
- Historigram (Correct answer)
- Histogram
- Line Graph
- Trend
Correct answer: Historigram
A historigram is the specific term for a graphical representation of a time series, where data points are plotted against time. It typically uses a line graph to show the evolution of a variable over successive time intervals. While it is a type of line graph, "historigram" is the more precise term in time series analysis for depicting data over time.
Question 2: The secular tendency has undergone the following movement(s).
- Regular
- Steady
- Smooth
- All of the above (Correct answer)
Correct answer: All of the above
The secular tendency, also known as the long-term trend, describes the general direction or movement of a time series over an extended period. This movement is typically characterized as regular, steady, and smooth, indicating a consistent underlying pattern of growth or decline, rather than short-term fluctuations. Therefore, all listed descriptions apply to the secular tendency.
Question 3: In a business, prosperity, recession, and depression are examples of this.
- Secular Trend
- Irregular Component
- Seasonal Component
- Cyclical Component (Correct answer)
Correct answer: Cyclical Component
Prosperity, recession, and depression are all stages of the business cycle, which represents the cyclical component of a time series. These are medium-term fluctuations in economic activity that typically last longer than a year but are not as long-term as a secular trend. They reflect the ebb and flow of the economy, driven by various economic factors.
Question 4: Moving averages are used to calculate the secular trend:
- Give the trend in a straight line
- Measures the seasonal variations
- Smooth out the time series (Correct answer)
- None of the above
Correct answer: Smooth out the time series
Moving averages are primarily used in time series analysis to smooth out short-term fluctuations and irregular variations in the data. By averaging values over a specific period, they help to reveal the underlying long-term trend (secular trend) more clearly, making it easier to identify the general direction of the series. This process filters out noise to highlight the main pattern.
Question 5: According to time series theory, a shortage of specific consumer items prior to the yearly budget is caused by
- Cyclinal Component
- Seasonal Component (Correct answer)
- Secular Trend
- Irregular Component
Correct answer: Seasonal Component
A shortage of specific consumer items prior to a yearly budget, if it occurs consistently around the same time each year, is an example of a seasonal component. This predictable pattern is often driven by annual events, such as pre-holiday shopping surges or anticipatory buying before a new fiscal year's price adjustments. It's a recurring short-term variation tied to the calendar.
Question 6: The term "observation set" refers to a collection of observations taken at regular intervals of time.
- Data
- Array data
- Time series data (Correct answer)
- Geometric Series
Correct answer: Time series data
Time series data is defined as a sequence of observations recorded at successive, equally spaced points in time. This regular interval is a defining characteristic, distinguishing it from other types of data. Examples include daily stock prices, monthly sales figures, or annual population counts, all of which are collected sequentially over time.
Question 7: A fire in a factory has caused production to be halted for several weeks is
- Cyclinal Component
- Secular Trend
- Seasonal Component
- Irregular Component (Correct answer)
Correct answer: Irregular Component
An irregular component in time series analysis refers to unpredictable, short-term fluctuations that are not part of a regular pattern. A fire causing production to halt is an unforeseen event, a one-off occurrence that doesn't follow a seasonal, cyclical, or long-term trend. This makes it a classic example of an irregular or random component affecting the time series data.
Question 8: Which trend may be eliminated using second differencing in time series?
- Linear Trend and Quadratic Trend
- Quadratic Trend (Correct answer)
- Linear Trend
- None of the above
Correct answer: Quadratic Trend
First differencing can eliminate a linear trend by calculating the change between consecutive data points. Second differencing applies this process again to the first-differenced series. This effectively transforms a quadratic trend into a linear one after the first difference, and then into a constant after the second difference, thereby eliminating the quadratic trend and helping to achieve stationarity.
Question 9: Ratio-to-trend analysis is a typical approach for determining
- Take moving average
- Remove multicollinearity
- Represent graphical curve
- Deseasonalize data (Correct answer)
Correct answer: Deseasonalize data
Ratio-to-trend analysis is a method used to isolate and measure the seasonal component in a time series. It involves calculating the ratio of actual observed values to the trend values, then averaging these ratios for corresponding periods to derive seasonal indices. These indices are then used to remove the seasonal effect from the original data, a process known as deseasonalization.
Time Series Analysis Test 1
The graph of a time series is referred to as