Question 1

The most common form of autocorrelation is positive autocorrelation,in which

Accepted Answer

Positive autocorrelation occurs when large values follow large values and small values follow small values in a data series, indicating a pattern or trend in the data.

Question 2

When using exponential smoothing,a smoothing constant  must be used.The value for

Accepted Answer

The answer of When using exponential smoothing,a smoothing constant ...

Question 3

In a moving averages method,which of the following represent(s)the number of terms in the moving average?

Accepted Answer

In the moving averages method, the number of terms in the moving average is represented by a span. This span determines how many previous data points should be used to calculate the average at any given time.

Question 4

In a random series,successive observations are probabilistically independent of one another.If this property is violated,the observations are said to be

Accepted Answer

When observations in a series are not independent, meaning the value of one observation can predict the value of another, they are said to be autocorrelated. This is in contrast to a random series where each observation is independent of the others.

Question 5

When using exponential smoothing,if you want the forecast to react quickly to movements in the series,you should choose

Accepted Answer

The answer of When using exponential smoothing,if you want the...

Question 6

The idea behind the runs test is that a random number series should have a number of runs that is

Accepted Answer

The runs test is based on the principle that a random sequence will have a number of runs (sequences of consecutive numbers that are either all increasing or all decreasing) that is neither excessively large nor small, indicating a random distribution without patterns.

Question 7

A linear trend means that the time series variable changes by a _____ each time period.

Accepted Answer

A linear trend in a time series variable indicates that the variable changes by a constant amount each time period, rather than by a percentage or exclusively positive or negative amounts.

Question 8

Which term refers to a consecutive series of observations that remain on one side of the base level?

Accepted Answer

A "run" refers to a sequence of similar items, in this context, a series of observations that are all either above or below a certain level without crossing it. This term is used in statistics to describe such patterns within data sets.

Question 9

In a random walk model,the series itself

Accepted Answer

In a random walk model, the series appears to follow a path where the differences (or changes) from one period to the next are random, but the series itself, being the cumulative sum of these random differences, does not behave randomly. This means that while the series may look unpredictable when observed at any single point, its structure—being a cumulative sum of random differences—follows a specific stochastic pattern.

Question 10

In contrast to linear trend,an exponential trend is appropriate when the time series changes by a _____ each time period.

Accepted Answer

An exponential trend is characterized by changes that occur by a constant percentage each time period, rather than a constant amount. This means the amount of change is proportional to the current value, leading to exponential growth or decay.

Question 11

The following are the values of a time series for the first four time periods: t
1
2
3
4  24
25
26
27
Using a four-period moving average,the forecasted value for time period 5 is

Accepted Answer

The answer of The following are the values of a...

Question 12

The random walk model is written as:  .In this model,  represents the

Accepted Answer

The answer of The random walk model is written as:...

Question 13

Holt's model differs from simple exponential smoothing in that it includes a term for

Accepted Answer

Holt's model extends simple exponential smoothing by incorporating a trend component in addition to the level component, allowing it to account for data with trends over time.

Question 14

The data below represents sales for a particular product.If you were to use the moving average method with a span of 3 periods,what would be your forecast for period 5? Period
Sales (in units)
1
90
2
120
3
110
4
100

Accepted Answer

The answer of The data below represents sales for a...

Question 15

Suppose that a simple exponential smoothing model is used (with  = 0.40)to forecast monthly sandwich sales at a local sandwich shop.The forecasted demand for September was 1560 and the actual demand was 1480 sandwiches.Given this information,what would be the forecast number of sandwiches for October?

Accepted Answer

The answer of Suppose that a simple exponential smoothing model...

Question 16

The linear trend  was estimated using a time series with 20 time periods.The forecasted value for time period 21 is

Accepted Answer

The answer of The linear trend  was estimated using...

Question 17

Perhaps the simplest and one of the most frequently used extrapolation methods is the

Accepted Answer

The answer of Perhaps the simplest and one of the...

Question 18

Suppose that a simple exponential smoothing model is used (with α = 0.30)to forecast monthly sandwich sales at a local sandwich shop.After June's demand is observed at 1520 sandwiches,the forecasted demand for July is 1600 sandwiches.At the beginning of July,what would be the forecasted demand for August?

Accepted Answer

The answer of Suppose that a simple exponential smoothing model...

Question 19

The runs test uses a series of 0's and 1's.The 0's and 1's typically represent whether each observation is

Accepted Answer

The runs test, particularly in the context of analyzing a series of 0's and 1's, is used to determine if the sequence is random or not. In this scenario, the 0's and 1's typically represent whether each observation is above or below the mean value of Y. This is a way to test for randomness or to detect patterns in the data that deviate from what would be expected in a random distribution of values.

Question 20

The moving average method can also be referred to as a(n)____ method.

Accepted Answer

The moving average method is a type of smoothing technique used in time series analysis to smooth out short-term fluctuations and highlight longer-term trends or cycles.

Quiz 12: Time Series Analysis and Forecasting

The most common form of autocorrelation is positive autocorrelation,in which

When using exponential smoothing,a smoothing constant must be used.The value for

In a moving averages method,which of the following represent(s) the number of terms in the moving average?

In a random series,successive observations are probabilistically independent of one another.If this property is violated,the observations are said to be

When using exponential smoothing,if you want the forecast to react quickly to movements in the series,you should choose

The idea behind the runs test is that a random number series should have a number of runs that is

A linear trend means that the time series variable changes by a _____ each time period.

Which term refers to a consecutive series of observations that remain on one side of the base level?

In a random walk model,the series itself

In contrast to linear trend,an exponential trend is appropriate when the time series changes by a _____ each time period.

The following are the values of a time series for the first four time periods: t 1 2 3 4 24 25 26 27 Using a four-period moving average,the forecasted value for time period 5 is

The random walk model is written as: .In this model, represents the

Holt's model differs from simple exponential smoothing in that it includes a term for

The data below represents sales for a particular product.If you were to use the moving average method with a span of 3 periods,what would be your forecast for period 5? Period Sales (in units) 1 90 2 120 3 110 4 100

The linear trend was estimated using a time series with 20 time periods.The forecasted value for time period 21 is

Perhaps the simplest and one of the most frequently used extrapolation methods is the

The runs test uses a series of 0's and 1's.The 0's and 1's typically represent whether each observation is

The moving average method can also be referred to as a(n) ____ method.