Date:         Mon, 8 Apr 1996 12:15:09 +0100
Reply-To:     John Whittington <johnw@MAG-NET.CO.UK>
Sender:       "SAS(r) Discussion" <SAS-L@UGA.CC.UGA.EDU>
From:         John Whittington <johnw@MAG-NET.CO.UK>
Subject:      Re: Weighted Average Means.
Comments: To: Alex Wolf <wolfam@WERPLE.NET.AU>

On Mon, 8 Apr 1996, Alex Wolf <wolfam@WERPLE.NET.AU> wrote:
 
>I am faced with a problem where I am filling Orders with a number of Lines
each having
>an average length and weight in Kilograms. I can do a Proc Summary using the
>Weight = Kilogram to produce a weighted Average Mean.
>
>In an example:
>
>Line1  Kilograms = 300,  Avg Length = 21.5
>Line2  Kilograms = 450,  Avg Length = 19.5
>
>Line?  Kilogram  =  250   Avg Length = ???
>
>Order needs 1000 Kilograms and an Average Length of 21.0.  I need to know
what the average length of a third Line to satisfy Order average requirement.
 
Alex, I am not convinced that I understand exactly how you want to do this
(in terms of where the data is coming from and going to), but the following
will do what I understand of the required arithmetic for you:
 
data info ;
    input kilo avlength ;
    cards ;
300 21.5
450 19.5
;
run ;
 
data _null_ ;
    set info nobs = obs ;
    wt_len = kilo * avlength ;
    sum_kilo + kilo ;
    sum_wtl + wt_len ;
    if _N_ = obs then do ;
        kilogram = 1000 - sum_kilo ;
        avg_len = (21000 - sum_wtl) / kilogram ;
        put 'LineX  ' kilogram = '   ' avg_len = ;
    end ;
run ;
 
John
 
-----------------------------------------------------------
Dr John Whittington,        Voice:      +44 1296 730225
Mediscience Services        Fax:        +44 1296 738893
Twyford Manor, Twyford,     E-mail:     johnw@mag-net.co.uk
Buckingham  MK18 4EL, UK    CompuServe: 100517,3677
-----------------------------------------------------------