Dear All,
A request for something that I've drawn a blank on.
In the old days I learned about Z (time series) Charts: they consist of
three curves; and when plotted they always form a letter Z.Spooky or what?
Anyway, I remember two out of the three curves:
curve one = the actual data
curve two = the actual data accumulated
but
curve three = can't remember and can't work it out.
Anyone have a stats book with such a thing, or that has a website address
they can point me at?
I'd be grateful.
Duncan Williamson
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