Deck 16: Time Series Trend

Question 1

A least-squares regression line for the annual profit trend of a small restaurant is calculated as being t = 35983 + 3567x. Estimate the time point value for year 6.

A) £57385
B) £53818
C) £60952
D) £64519

Answer 1

£57385

Question 2

Which statement concerning the semi-averages method is NOT correct?

A) Both the lower and upper groups should have the same number of data points
B) Mean values for the lower and upper groups are plotted against the median value of the group
C) Data should be arranged in order of size from smallest to largest data point
D) If the data set contains an odd number of points the middle point should be ignored

Answer 2

Data should be arranged in order of size from smallest to largest data point

Question 3

Which of these statements concerning the choice of technique for extracting the trend is NOT correct?

A) The moving average method is disadvantaged by not having values for the start and end data points
B) The least squares regression method is suitable for use with highly seasonal data
C) Semi-average and least squares regression techniques always result in a straight-line trend
D) The moving average method is able to show the true nature of the trend in the data

Answer 3

The least squares regression method is suitable for use with highly seasonal data

Question 4

Which of the following statements concerning the moving average method of calculating a trend is NOT true?

A) The number of values used to calculate the moving average is called the period
B) Values should be chosen so that numbers used to calculate the moving average do not overlap
C) The number of values used to calculate the moving average should always be the same
D) There will always be a smaller number of moving average values than original data points

Question 5

Which of the following statements about time series trends IS true?

A) A time series can always be expressed as a straight line
B) A time series comprises, trend, seasonal and residual components
C) The trend component of a time series may fluctuate in a cyclical fashion
D) A trend should always show an increase over time

Question 6

What technique is used to place moving average values when the length of the period is even?

A) Fixing
B) Averaging
C) Splitting
D) Centering

Question 7

Data for the number of containers unloaded at the Port of Shanghai is collected every day. Values for the last 7 days are to be used as the upper group in a semi-average calculation. Work out the average (mean) for this group (1 decimal place): 85,235; 92,467; 63,287; 95,402; 86,263; 74,224; 89,123

A) 83714.4
B) 83714.5
C) 83714.0
D) 83714.3

Question 8

Which of the following options is NOT a way to extract a trend from time series values?

A) Least-squares regression
B) Moving averages
C) Semi-averages
D) Floating averages

Question 9

When calculating a moving average of a data set with a natural cycle of 6 months, what should be the length of the period?

A) 4
B) 12
C) 6
D) 2

Question 10

When analysing a data set of 35 points, with a period length of 7, how many moving average values will be generated?

A) 35
B) 33
C) 31
D) 29