Home › Forums › General Forums › Methodology › FTY=e-DPU
This topic contains 11 replies, has 9 voices, and was last updated by Mike Carnell 1 year, 7 months ago.
I am confused as to how to obtain the FTY using a constant e-2.718 can someone enlighten me?
i.e.
FTY= e -DPU
e-2.718
FTY=2.718 -0.3
FTY=0.741
FTY=74%
How did this get calculated? HELP!
Do some research on the Poisson equation, this site or elsewhere.
True, also needed a elaborated question. Self study here, will save you time.
I believe this formula is referring to RTY not FTY if memory serves, and obtaining it involves simply taking the natural log (e^x) of the negative dpu measure. – it took me three key strokes on the calculator.
just one state RTY=FTY if defect=0
and as I know RTY= e -DPU when we would like to calculate as a short term but long term you should to multiplication every DPU for each process.
You probably already figured this out, but … The exercise to figure FTY uses an exponent for DPU, expressed as a negative. So your expression
FTY= e (constant) -DPU (to the power expressed)
e-2.718
FTY=2.718 -0.3 (power of negative .3)
FTY=0.741
FTY=74%
I don’t have a scientific calculator so I used Excel, where the formula is shown as “=POWER(2.718,-0.3)”
It’s RTY….not FTY.
….well Chris, I suppose if the production line was moving really fast you might be able to get the product airborne in which case it would be flying and not rolling…. :-)
LOL…..
How about this kind of flying item?
@rbutler – Good one, Robert. You’re getting punnier, and punnier all the time!
@cseider – One of the more bizzaro sitcoms – even for its day. Seriously, the lift to weight ratio for a habit that size would at best lift a midget, I don’t care how little Sally Field weighed. And no vertical stabilizers? Please, totally aerodynamically infeasible, totally unstable (but then, maybe that was a metaphor for Sally?).
Hi,
FTY=e-DPU (e minus DPU or e raised to the negative power of DPU)
RTY=e-total DPU (e minus total DPU)
DPU=-ln(FTY) (negative logarithm of FTY)
e= 2.718 which is a constant value.
Example:- If DPU is 0.008928571 then (if you calculate in Excel) FTY = =POWER(2.718,-0.008928571) = 0.991111663 or 99.11%.
DPU=-ln(FTY),(if you calculate in Excel)=-LN(0.991111663
)=0.008928571.
Also calculate p(d) probability of defets and find Z value from Z table.
p(d) = 1-Yield.
@cjdawgct As several people have tried to explain this is an estimate of Rolled Throughput Yield. It is an estimate. The higher the defect level the less accurate the estimate. Once you are over a 10% defect level it is probably inaccurate enough that you wouldn’t want to use it.
When you are getting stats advice from @cseider, @MBBinWI and @MBBinWI to need to pay attention because these guys are very good. When you get stats advice from @rbutler it isn’t going to get any better even if you pay for it.
Just my opinion.
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