CUMULATIVE AVERAGE

CUMULATIVE AVERAGE (LET)

Let Subcommand

Compute the cumulative average of a variable.

The cumulative average, Y2, of a variable Y is defined as:
Y2(1) = Y(1)
Y2(2) = (Y(1) + Y(2))/2
Y2(3) = (Y(1) + Y(2) + Y(3))/3
etc.


That is, the cumulative mean of an element in a variable is simply the mean of all points in the variable up to and including that element.

LET <y2> = CUMULATIVE AVERAGE <y1>             <SUBSET/EXCEPT/FOR qualification>
where <y1> is a response variable;
            <y2> is a variable where the cumulative average is stored;
and where the <SUBSET/EXCEPT/FOR qualification> is optional.

LET Y2 = CUMULATIVE AVERAGE Y
LET Y2 = CUMULATIVE AVERAGE Y FOR I = 1 1 30

None

CUMULATIVE MEAN is a synonym for CUMULATIVE AVERAGE.

MEAN	Compute the mean of a variable.
CUMULATIVE SUM	= Compute the cumulative sum of a variable.
CUMULATIVE PRODUCT	= Compute the cumulative product of a variable.
CUMULATIVE INTEGRAL	= Compute the cumulative integral of a variable.

Data Manipulation

1998/5

SKIP 25
READ HAHN.DAT Y
LET YAVE = CUMULATIVE AVERAGE Y