Unit 10: Time Series - Practice Quiz

ECAP790 60 Questions
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1 What is a time series?

Introduction to time series Easy
A. Data recorded in chronological order
B. Data grouped without reference to time
C. Data arranged in alphabetical order
D. Data collected from one location only

2 Which of the following is an example of time-series data?

Introduction to time series Easy
A. Monthly sales of a store
B. Heights of students in a class
C. Colors of cars in a parking lot
D. Names of employees in a company

3 In a time series, the independent variable is usually:

Introduction to time series Easy
A. Time
B. Category
C. Location
D. Frequency

4 Which graph is commonly used to display a time series?

Introduction to time series Easy
A. Pictogram showing every individual observation with a separate symbol
B. Venn diagram
C. Pie chart
D. Line graph

5 What is a major purpose of time-series analysis?

Introduction to time series Easy
A. To calculate only the total number of observations
B. To arrange words alphabetically
C. To classify objects by color
D. To study changes over time

6 Which set of observations is recorded at regular time intervals?

Introduction to time series Easy
A. Daily temperatures
B. Book titles
C. Student roll numbers
D. Types of soil found at several unrelated locations during one survey

7 Which component represents the long-term general movement of a time series?

Components of time series Easy
A. Seasonal variation
B. Irregular variation
C. Cyclical variation
D. Trend

8 Which component consists of patterns that repeat within one year?

Components of time series Easy
A. Seasonal variation
B. Irregular variation caused by completely unexpected and nonrecurring events
C. Secular trend
D. Cyclical variation

9 An increase in ice-cream sales every summer is an example of:

Components of time series Easy
A. Irregular variation
B. Secular trend
C. Seasonal variation
D. Cyclical variation

10 Which variation is associated with long-term business expansions and recessions?

Components of time series Easy
A. A constant movement that repeats every week throughout a single year
B. Seasonal variation
C. Irregular variation
D. Cyclical variation

11 A sudden fall in production due to an earthquake is classified as:

Components of time series Easy
A. Seasonal variation
B. Cyclical variation
C. Secular trend
D. Irregular variation

12 Which list contains the four standard components of a time series?

Components of time series Easy
A. Trend, frequency, probability, correlation, and regression
B. Primary, secondary, discrete, continuous
C. Mean, median, mode, range
D. Trend, seasonal, cyclical, irregular

13 In the additive time-series model, an observation is represented by:

Components of time series Easy
A.
B.
C.
D.

14 In the multiplicative time-series model, the components are:

Components of time series Easy
A. Added together
B. Converted into frequencies and then arranged into class intervals
C. Subtracted in order
D. Multiplied together

15 Which method estimates trend by drawing a smooth line through plotted observations?

Measurement of variations of time series Easy
A. Ratio-to-trend method using seasonal percentages for each period
B. Moving average method
C. Freehand curve method
D. Semi-average method

16 Which trend-measurement method divides a time series into two equal parts?

Measurement of variations of time series Easy
A. Moving average method
B. Least-squares method
C. Semi-average method
D. Link-relative method

17 What is the main purpose of a moving average?

Measurement of variations of time series Easy
A. To increase seasonal variation
B. To create random fluctuations
C. To replace every observation with the largest value in the entire series
D. To smooth short-term fluctuations

18 What is the three-period moving average of , , and ?

Measurement of variations of time series Easy
A.
B.
C.
D.

19 Which method fits a trend line by minimizing the sum of squared errors?

Measurement of variations of time series Easy
A. A seasonal method based only on comparing the highest annual values
B. Freehand curve method
C. Least-squares method
D. Semi-average method

20 A seasonal index of indicates that the value is typically:

Measurement of variations of time series Easy
A. Exactly equal to the average
B. below the average
C. above the average
D. below the average

21 A company records its monthly sales for five consecutive years. Why is this data considered a time series?

Introduction to time series Medium
A. The observations have equal arithmetic means
B. The observations are collected from several companies
C. The observations are arranged in chronological order
D. The observations contain only numerical variables

22 Which data set is most suitable for time-series analysis?

Introduction to time series Medium
A. Test scores of four classes in one semester
B. Daily closing prices of one stock for a year
C. Heights of 200 students measured on one day
D. Annual incomes of 100 households in one city

23 Quarterly revenue was recorded as , , , and million. What does the time-series value million represent?

Introduction to time series Medium
A. Revenue recorded during the third quarter
B. Average revenue across all four quarters
C. Difference between two consecutive quarters
D. Revenue forecast for the fourth quarter

24 A retailer wants to forecast demand that changes noticeably from month to month. Which recording frequency is most appropriate?

Introduction to time series Medium
A. Monthly observations
B. Decennial observations
C. Five-year observations
D. One cross-sectional observation

25 Which statement best distinguishes time-series data from cross-sectional data?

Introduction to time series Medium
A. Time-series data track a variable across successive times
B. Time-series data must always be recorded every day
C. Time-series data cannot contain nonperiodic fluctuations
D. Time-series data compare many units at one fixed time

26 Ice-cream sales rise each summer and fall each winter in a broadly repeated pattern. Which component primarily explains this movement?

Components of time series Medium
A. Irregular variation
B. Cyclical variation
C. Seasonal variation
D. Secular trend

27 A country's real output alternates between expansion and recession over periods lasting several years. Which time-series component does this illustrate?

Components of time series Medium
A. Daily variation
B. Seasonal variation
C. Cyclical variation
D. Irregular variation

28 A factory's production drops suddenly because of an unexpected earthquake. Which component best represents this change?

Components of time series Medium
A. Cyclical variation
B. Secular trend
C. Seasonal variation
D. Irregular variation

29 A city's population increases steadily over three decades despite short-term fluctuations. Which component is represented by the sustained increase?

Components of time series Medium
A. Seasonal variation
B. Irregular variation
C. Cyclical variation
D. Secular trend

30 Under the additive model of a time series, which equation represents an observation ?

Components of time series Medium
A.
B.
C.
D.

31 A multiplicative model is generally more appropriate when seasonal fluctuations:

Components of time series Medium
A. Increase in magnitude as the series level rises
B. Disappear whenever the trend becomes positive
C. Remain constant in magnitude at every series level
D. Occur only once during the observed period

32 In an additive model, , , , and . What is the irregular component ?

Components of time series Medium
A.
B.
C.
D.

33 Annual sales for four consecutive years are , , , and units. Using the semi-average method, what are the two semi-averages?

Measurement of variations of time series Medium
A. and
B. and
C. and
D. and

34 For observations , , and , what is the centered three-period moving average assigned to the middle period?

Measurement of variations of time series Medium
A.
B.
C.
D.

35 Why is a four-quarter moving average usually centered before it is aligned with quarterly observations?

Measurement of variations of time series Medium
A. Its computation excludes the seasonal component
B. Its total must equal four before interpretation
C. Its values always contain strong irregular variation
D. Its average initially falls between two quarters

36 A fitted linear trend is , where corresponds to 2024. What is the trend estimate for 2027?

Measurement of variations of time series Medium
A.
B.
C.
D.

37 When time values are coded so that , which formula gives the least-squares estimate of the intercept in ?

Measurement of variations of time series Medium
A.
B.
C.
D.

38 In the ratio-to-moving-average method, an observed quarterly value is and its centered moving average is . What is the seasonal relative?

Measurement of variations of time series Medium
A.
B.
C.
D.

39 The unadjusted quarterly seasonal indices are , , , and . Is an adjustment required before using them?

Measurement of variations of time series Medium
A. Yes, because each index must equal
B. No, because their average is
C. Yes, because their sum must be
D. No, because their sum is

40 A multiplicative time series has an observed value of and a seasonal index of . What is the seasonally adjusted value?

Measurement of variations of time series Medium
A.
B.
C.
D.

41 Two series contain exactly the same observed values but in different chronological orders. Which statistic can differ between them solely because of the reordering?

Introduction to time series Hard
A. The sample median
B. The lag-1 autocorrelation
C. The sample variance
D. The sample mean

42 A forecasting model is evaluated by randomly assigning observations from a strongly autocorrelated time series to training and test sets. What is the principal methodological problem?

Introduction to time series Hard
A. The test set necessarily has a larger variance
B. Random assignment eliminates the seasonal component
C. The fitted model becomes algebraically unidentified
D. Temporal dependence can leak future information into training

43 A monthly series is , where is a deterministic monthly effect and . If each year's value is formed by averaging its 12 months, what series results?

Introduction to time series Hard
A. An annual series with an increasing trend
B. A constant annual series equal to
C. A constant annual series equal to
D. A seasonal annual series with period

44 Which pair of constraints most directly makes the seasonal component identifiable in standard additive and multiplicative decompositions, respectively?

Components of time series Hard
A. and
B. and
C. and
D. and

45 Under the additive model , suppose . At , , , and . What is ?

Components of time series Hard
A.
B.
C.
D.

46 For the multiplicative model , an observation has , , , and . What is the irregular factor?

Components of time series Hard
A.
B.
C.
D.

47 The seasonal fluctuations of a sales series are approximately units when its level is and units when its level is . Which decomposition is most appropriate before further diagnostics?

Components of time series Hard
A. An additive model, because the absolute amplitude increases
B. A multiplicative model, because the relative amplitude is stable
C. An additive model, because the relative amplitude decreases
D. A trend-only model, because seasonality is level-dependent

48 Suppose a quarterly additive series is , where repeats every four quarters. Ignoring irregular variation, what is ?

Components of time series Hard
A.
B.
C.
D.

49 A series displays recurrent expansions and contractions lasting between three and seven years, with no fixed duration or calendar timing. Which component best describes this behavior?

Components of time series Hard
A. Secular trend
B. Irregular variation
C. Seasonal variation
D. Cyclical variation

50 If with all factors positive, which transformation converts the decomposition into an additive form without approximation?

Components of time series Hard
A.
B.
C.
D.

51 For quarterly observations , what is the centered four-quarter moving average aligned with the third observation?

Measurement of variations of time series Hard
A.
B.
C.
D.

52 Let , where has period and its five values sum to zero. Away from the endpoints, what does a centered five-term moving average equal exactly?

Measurement of variations of time series Hard
A.
B.
C.
D.

53 Raw quarterly seasonal indices are . After normalizing them so that their sum is , what is the normalized index for the third quarter?

Measurement of variations of time series Hard
A.
B.
C.
D.

54 A least-squares trend is fitted to using . What is the forecast corresponding to the next coded value ?

Measurement of variations of time series Hard
A.
B.
C.
D.

55 Annual observations for years 1 through 6 are . Using the semi-average method, what is the trend forecast for year 7?

Measurement of variations of time series Hard
A.
B.
C.
D.

56 An observed quarterly value is , and its multiplicative seasonal index is on a base- scale. What is the deseasonalized value?

Measurement of variations of time series Hard
A.
B.
C.
D.

57 In the link-relative method, February, March, and April have link relatives , , and , respectively. If January's chain relative is , what is April's chain relative before drift correction?

Measurement of variations of time series Hard
A.
B.
C.
D.

58 An exponential trend has the form . If and , with , what is the trend value at ?

Measurement of variations of time series Hard
A.
B.
C.
D.

59 Centering two adjacent four-term simple moving averages produces a five-observation weighted moving average. What are its weights from earliest to latest observation?

Measurement of variations of time series Hard
A.
B.
C.
D.

60 Under , suppose , , , and . What is the estimated cyclical factor?

Measurement of variations of time series Hard
A.
B.
C.
D.