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Conference rusure::math

Title:Mathematics at DEC
Moderator:RUSURE::EDP
Created:Mon Feb 03 1986
Last Modified:Fri Jun 06 1997
Last Successful Update:Fri Jun 06 1997
Number of topics:2083
Total number of notes:14613

1783.0. "exponential average ?" by EVTAI1::TRICHET (e4e5Cf3Cc6Fc4Cg5) Tue Aug 24 1993 07:45

    
    I have been told about the exponential average of  n  datas
    
    Something like 
    
    	EA(n) = a Y(t) + (1-a) EA(t-1)
    
    With EA : expon. aver. of the last n datas.
              Y(t) data value at time t
    	      Y(t-1) data value the time before (t-1)
    	      a = 2 / (n+1)
    
    Does somebody known the formula which gives EA(t) without EA(t-1) ?
    
    PAscal;
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1783.1FORTY2::PALKATue Aug 24 1993 13:0514
    Something like.
    
                i=t
                __
                \           (t-i)
    EA(t) =     /    a (1-a)       Y(i)
                --
                i=0
    
    
    Note that EA depends on all the previous Y(t), not just the previous n.
    However the effect of the older ones is very small.
    
    Andrew
1783.3<thanks>EVOAI2::$TRICHET$ Spawn/nowait dir /output=nl:Tue Aug 24 1993 14:467
     
    Thanks for quick answer
    
    It is going to be used for financial purpose
    as MACD theory (Moving Average Convergence Divergence)
    
    Pascal