How-To Use the Histogram, Cp and CpK tools in QI Macros 2010 for Six Sigma Project

This is a how-to video, done as a screencast, that shows how to create a histogram using QI Macros 2010. Cp and CpK for processes is also covered. A histogram is a popular tool used in Lean Six Sigma projects. It is one of the tools introduced in the online Lean Six Sigma Green Belt course offered by Purdue University through Engineering Professional Education.

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Closed Caption:

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my I'm
today we're going to look at how to
create a histogram how to calculate CP
and CPK
measures a process control you think
your macros
you'll see I have some sample data in my
spreadsheet here
for diameter no se said amor shaft on a
car
a pretty big cars are four inch diameter
shaft against and an hour early cue a
macro stab
as a couple ways to get to the histogram
our CP and CPK
there's one right on the Main tab if
your macros this is Excel 2010
2007 is very similar
and Excel 2003 has a slightly different
menu structure but but you can also get
to the histogram under SPC charts
and maybe a couple other places are more
than one way to get to the
histogram with CP and CPK but will go
straight back to
them Main tab there no first VoIP
selector data
many tabs sometimes you're just like
your day to advance sometimes have to
set your day
data in a table sometimes you just have
to have your daily in the right number
of columns in the right order
or going to select a column called
diameter hazard
our sample data in it right click on
histogram CP and CPK
now the subgroup letters group our data
now for the histogram it taken every we
have thirty data points at thirty bars
on histogram
are 30 saturday on the history and kinda
busy are so we're gonna
average those out organisers subgroup
sizeof three
and now rocking are stacked limit
the spec limit is how close to the range
our actual measured value years to what
the process will allow so if we say our
4-h
Shacknews to be between 4.1 and 3.9
to be with inspected with Sarah perspect
limit or a Petare slum into being a
college
iOS 4.1 we enter it here and are lower
spec laminer Lord harsh limit
is 3.9 so we do that
how how many bars on the on the
histogram
a it's not a big deal usually default
value like %um actors okay we were
recruited a subgroup Turkana smooth and
our data
and the warrant for a title on a short
the x-axis y-axis so we gotta count of
how many values
for how many lawyers a 4.01
now we take a look at the state it looks
fairly normal you see the standard I'll
curve
any respect limit you've got a red line
it up respect a woman in a red line to
lower spec love it
for clients here and here and that tells
you
you can see if any have your values in
the histogram are actually outside that
range than you know your
just by visually or processes is
definitely out of control
now we take a look at the CP and CPK
values
are calculated in this data for
spectrometer 4.1
what we don't have any data point over
buffer limited data set
the process controller is 1.66 that
typically
I am most people
interpret a process and control is 1.33
whereas technically one is a process and
control
but for long-term drifter a process that
they look at
how 1.33 is being a minimum and for many
companies they require is 1.67 secrecy
are CPK value in this case at point six
sixes
represents a process that is not in
control even though it looks
pretty good on the on the chart
inside the red lines it's not far enough
away from the red lines
and there's too much variance across the
the value so
if we take a look somewhere we could
find the standard deviation
point 04 so three standard deviations
for the me would be 4.12
and 3.88 so both of those are
for beyond our spec limit above and
below our spec limits which means
that based on three standard deviations
from the mean
this process is not quite control so
it's not too bad
but it's certainly not a successful
process and
visually you could tell that by the
number of bars there spread away from
the center
how flap this bell curve years the
tighter the process the more overtime
peak that you'll see on your Booker
means