Which of the following time series is not likely to have a seasonal effect?

1.   ?    Weekly sales of chocolate bars at a corner shop
2.   ?    Number of staff at an insurance company absent from work each day
3.   ?    The number of households owning a personal computer each year
4.   ?    Monthly unemployment figures for the UK

The computer department of a large store uses exponential forecasting with a smoothing constant of 0.3 to forecast sales the following day. If sales on day 1 are 10 and on day 2 are 6, how many sales will be forecast for day 3? Start calculations by using day 1 sales to forecast day 2.

1.   ?    8.8
2.   ?    11.2
3.   ?    4.8
4.   ?    7.2

A series of demand figures and exponential forecasts are shown below. Which smoothing constant has been used? Forecasts have been rounded to 1 d.p. at each stage in the calculations.
Demand 50, 46, 48, 62, 68, 54, 59, 61, 53
Forecast   50, 47.6, 47.8, 56.3, 63.3, 57.7, 58.5, 60.0.

1.   ?    0.4
2.   ?    0.6
3.   ?    0.5
4.   ?    0.2

For the demand figures and forecasts given in question 3, calculate the mean squared error?

1.   ?    6.29
2.   ?    50.33
3.   ?    55.19
4.   ?    62.27

If a time series is very irregular, what value of smoothing constant is likely to be most appropriate?

1.   ?    Close to 0
2.   ?    0.5
3.   ?    Close to 1
4.   ?    0.8

Exponential forecasting is appropriate in which of the following cases:

1.   ?    when there is a trend but no seasonal effect
2.   ?    when there is no trend but there is a seasonal effect
3.   ?    when there is no trend and no seasonal effect
4.   ?    when there is a trend and a seasonal effect

If we have the following time series and create a centred moving average series using 4 time periods, what value corresponds to time period 3?
Time 1 2 3 4 5
Series 20 18 23 21 22

1.   ?    20.5
2.   ?    20.75
3.   ?    21
4.   ?    23

Which of the following statements is not true?

1.   ?    Centred moving averages can eliminate seasonal effect
2.   ?    Centred moving averages estimate the underlying trend of a series
3.   ?    Regression can be used to estimate the trend of a series
4.   ?    A centred moving average can be calculated for all the data in a series

Which of the following steps is not carried out when calculating seasonal indices using a multiplicative time series model.

1.   ?    Subtract the estimated trend series from the original series
2.   ?    Estimate the trend series
3.   ?    Divide the original series by the trend series
4.   ?    Adjust the indices so that they average 1

10. Sales of paperback books from a particular outlet each month are assumed to follow an additive model. A least squares line is found to be sales = 25.8 + 1.05month. Seasonal indices have been calculated as
Season 1 2 3 4
4.76 0.28 -2.35 -2.69
Assuming month 13 falls in season 1, forecast sales for this month.

1.   ?    39.45
2.   ?    44.21
3.   ?    40.45
4.   ?    31.61