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EWMA control chart
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13. Control charts building: EWMA
Part 1
:
Introduction to
SPC
Part 2
:
Essential
concepts to
start with SPC
Part 4
Conclusion
Part 3
:
SPC in
practice
A
NALYZE
Individual value
/
Moving Range
Type of drifts to detect
Control charts
Small
and
slow
Ex.: wrong
adjustment of linac’s
parameters, errors
during
measurement…
Ex.: drift of the
detector’s dose
response
Diff. mes/calc. (%)
Patient number
EWMA
- Exponentially
Weighted Moving
Average -
Patient number
Diff. mes/calc. (%)
Large
and
Fast
(I,MR)
l
/
o i
nge
1
03/10/17
Patient #
Beam #