HP 3000 Manuals

HP RXForecast Users Manual for MPE Systems

Seasonality Level Option 

The Seasonality Level option appears on the RXForecast Options command
dialog box.


            

You use this option to control the level of seasonality that is included
in the model.  You can check from one to five of the seasonality levels
at the same time.

   *   Day of Week. 

       Remember that you define the day when you select the Shift and
       define the Start and Stop times.

   *   Week of Month. 

       Most months have more than 4 weeks (28 days).  All months are
       standardized to have 4 virtual weeks.  That is, each week is
       defined as follows:

       Week                  Definition                                                                                              

       Week 1                The first seven days of the month.

       Week 4                The last seven days of the month.

       Week 2                Half of the days remaining after weeks 1 and
                             4 are determined.  In months with 29 and 31
                             days, week 2 will consist of 7 and 8 days,
                             respectively.

       Week 3                Half of the days remaining after weeks 1 and
                             4 are determined.  In months with 29 and 31
                             days, week 3 will consist of 8 and 9 days,
                             respectively.

       Table 7-1  explains how weeks are defined for months of varying
       sizes.

          Table 7-1.  RXForecast Week Definition 

-----------------------------------------------------------------------------------------------------
|                   |                   |                   |                   |                   |
|  Number of Days   |      Week 1       |      Week 2       |      Week 3       |      Week 4       |
|                   |                   |                   |                   |                   |
-----------------------------------------------------------------------------------------------------
|                   |                   |                   |                   |                   |
|        28         |      1st-7th      |     8th-14th      |     15th-21st     |     22nd-28th     |
|                   |                   |                   |                   |                   |
-----------------------------------------------------------------------------------------------------
|                   |                   |                   |                   |                   |
|        29         |      1st-7th      |     8th-14th      |     15th-22nd     |     23rd-29th     |
|                   |                   |                   |                   |                   |
-----------------------------------------------------------------------------------------------------
|                   |                   |                   |                   |                   |
|        30         |      1st-7th      |     8th-15th      |     16th-23rd     |     24th-30th     |
|                   |                   |                   |                   |                   |
-----------------------------------------------------------------------------------------------------
|                   |                   |                   |                   |                   |
|        31         |      1st-7th      |     8th-15th      |     16th-24th     |     25th-31st     |
|                   |                   |                   |                   |                   |
-----------------------------------------------------------------------------------------------------

   *   Month of Quarter. 

   *   Quarter of Year. 

       Quarter always refers to the calendar quarter, not a fiscal
       quarter.

   *   Auto.  Seasonality. 

       Auto Seasonality works in conjunction with Day of Week, Week of
       Month, Month of Quarter, and Quarter of Year seasonality.  When
       you choose Auto Seasonality, HP RXForecast calculates seasonality
       for any and all of the seasonality levels you have selected.  Then
       it calculates whether any of the selected seasonality levels are
       significant; that is, the T-Probability is greater than 90
       percent.

       If it does find significant seasonality, HP RXForecast includes it
       in the forecast.  Conversely, insignificant seasonality is
       excluded.

       If Auto Seasonality is not checked, the levels of seasonality
       selected are forced into the model unless sufficient data does not
       exist.  If sufficient data does not exist, the appropriate levels
       will be removed so that a forecast can still be generated.


            

See "Seasonality and the Business Unit File"  for an explanation of
how to handle seasonality when using the Business Units trending method.

MPE/iX 5.0 Documentation