(@ average list @fp +-
    (0 .weight .divider .total ..)
    (# records-in list (@ item +-
                           (+= 1 .weight)
                           (+= (* weight (# fp item)) .total)
                           (+= weight .divider)
                       )
    )
    ([divider] >
        ((/ divider) total)
    >
        0
    )
+
    {A|L} list
)



