MOVINGAVERAGE

The MOVINGAVERAGE function (abbreviated MVAVG) computes a series of averages for the values of a dimensioned variable or expression over a specified dimension. For each dimension value in status, MOVINGAVERAGE computes the average of the data in the range specified, relative to the current dimension value.

When the data being averaged has only one dimension, MOVINGAVERAGE produces a single series of averages, one for each dimension value in status. When the data has dimensions other than the one being averaged over, MOVINGAVERAGE produces a separate series of averages for each combination of values in the status list of the other dimensions.

Return Value

DECIMAL when the data type of expression is DECIMAL or SHORT; otherwise, NUMBER.

Syntax

MOVINGAVERAGE(expression, start, stop, step, -

     [dimension [STATUS|limit-clause]])

Parameters

expression

A numeric variable or calculation whose values you want to average; for example, units or sales-expense.

start

stop

Integer values that specify the range of values over which you want to average. The value of start specifies the beginning of the range. The value of stop specifies the end of the range. Specify the values of start and stop relative to the current value of dimension. To specify a negative position for start or stop preceed the value with a comma. Thus, you specify zero (0) for the current dimension value, and -1 for the value preceding the current value. (See also "How the Moving Functions Handle Out-of-Range and NA Values".)

Note:

By default this function uses the default status list when identifying the range of values to average. You can specify either the STATUS or limit-clause phrase to change this behavior.

Tip:

When you want to range to the end of status, for convience and to document your intent, specify the value of stop as OBJ function with the DIMMAX keyword

step

A positive whole number that specifies whether to average over every value in the range, every other value, every third value, and so on. A value of 1 for step means average over every value. A value of 2 means average over the first value, the third value, the fifth value, and so on. For example, when the current month is Jun96 and the start and stop values are -3 and 3, a step value of 2 means average over Mar96, May96, Jul96, and Sep96.

dimension

The dimension over which the moving average is calculated. The data type of dimension can be of any type, but typically, is a time dimension.

When expression has a dimension with a type of DAY, WEEK, MONTH, QUARTER, or YEAR and you want the function to use that dimension, you can omit the dimension argument.

STATUS

Specifies that MOVINGAVERAGE should use the current status list (that is, only the dimension values currently in status in their current status order) when calculating the moving average.

limit-clause

Specifies that MOVINGAVERAGE uses the values specified by a LIMIT function or those specified with the same syntax as any of the limit-clause arguments in the various forms of the LIMIT command (that is, the syntax of the LIMIT command after the limit-type argument such as "TO"). For the syntax of these arguments, see LIMIT (using values) command, LIMIT using LEVELREL command, LIMIT (using parent relation), LIMIT (using related dimension) command, LIMIT NOCONVERT command, and LIMIT command (using POSLIST).

Usage Notes

How the Moving Functions Handle Out-of-Range and NA Values

As a moving function loops through the values, at each step in the loop, if the in-loop dimension position is NA or out of range, then the function considers expression as an NA value. The function treats these NA values in the manner specified by the setting of the NASKIP option (by default, as NA) so, typically, the function ignores out-of-range (NA) values and does not evaluate the expression for that step in the loop.

Examples

LIMIT product TO 'Womens - Trousers'
LIMIT timelevelnames TO 'Quarter'
LIMIT time TO time.levelrels
LIMIT time REMOVE 'Q1-1999' 'Q2-1999' 'Q3-1999'

REPORT DOWN time sales -
HEADING 'Running Yearly\nTotal' MOVINGTOTAL(sales, -4, 0, 1, time, -
     LEVELREL time.levelrels) -
HEADING 'Minimum\nQuarter' MOVINGMIN(sales, -4, 0, 1, time, -
     LEVELREL time.levelrels) -
HEADING 'Maximum\nQuarter' MOVINGMAX(sales, -4, 0, 1, time, -
     LEVELREL time.levelrels) -
HEADING 'Average\nQuarter' MOVINGAVERAGE(sales, -4, 0, 1, time, -
     LEVELREL time.levelrels)

-----------------------PRODUCT------------------------
               ------------------Womens - Trousers-------------------
                          Running
                          Yearly     Minimum    Maximum    Average
TIME           SALES      Total      Quarter    Quarter    Quarter
-------------- ---------- ---------- ---------- ---------- ----------
Q4-1999         416            1,386        233        480     346.50
Q1-2000         465            1,851        233        480     370.20
Q2-2000         351            1,969        257        480     393.80
Q3-2000         403            2,115        351        480     423.00
Q4-2000         281            1,916        281        465     383.20
Q1-2001         419            1,919        281        465     383.80
Q2-2001         349            1,803        281        419     360.60
Q3-2001         467            1,919        281        467     383.80
Q4-2001         484            2,000        281        484     400.00
Q1-2002         362            2,081        349        484     416.20
Q2-2002         237            1,899        237        484     379.80
Q3-2002         497            2,047        237        497     409.40
Q4-2002         390            1,970        237        497     394.00