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Statistical techniques




               5.7  Limitations of time series analysis

                                  There is an assumption that what has happened in the past is a
                                   reliable guide to the future.

                                  There is an assumption that a straight-line trend exists.

                                  There is an assumption that seasonal variations are constant,
                                   either in actual values using the additive model (such as dollars of
                                   sales) or as a proportion of the trend line value using the
                                   multiplicative model.



                  Illustrations and further practice



                  Now try TYU questions 7 and 8 from Chapter 12.




















































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