C3. Control Charts | Ask Lex PH Academy | YouTubeToText
YouTube Transcript: C3. Control Charts
Skip watching entire videos - get the full transcript, search for keywords, and copy with one click.
Share:
Video Transcript
hi there in this section we will discuss
control charts a statistical control
chart is a line graph
of the measurements of a product or
process over time
that has statistically based control
limits placed on it
just imagine what you learn from analyze space
space
a time series chart complicated by
statistical control limits
the points that are plotted on the
control chart may be the actual
measurements of a part characteristic
or summary statistics from samples or subgroups
subgroups
these are from parts taken as they are
produced over time
a control chart has control limits based upon
upon
process variation and a center line
representing the average of all the measurements
measurements
used to construct the control chart why
we have to use a control chart
a control chart displays and manages the variation
variation
in process output over time as we discuss
discuss
in analyze space a time series is used
to check the performance of our kpi
or our output over time similarly because
because
control chart is one type of time series
chart it does the same
it also helps identify when a process changes
changes
just like detecting patterns this is also
also
a basis for us to improve if we see that
the performance over time
is degrading then it's a signal for us
to improve
it helps us to identify the causes of variation
variation
and eventually use this data for process
capability analysis
it is also used to distinguish what we
call special causes of variation
from common causes of variation that is
when the correct sporadic problems or
when to change the process
here is an anatomy of a control chart
as you can see here the block dots
are plotted data points coming from a process
process
this is based on an x-axis which represents
represents
a time period remember a time series
has a y that is either continuous or
attribute and an x that is always
a measure of time we have here a green line
line
representing the average of the
measurements of the plotted points
we have now what we call the control limits
limits
above the center line and the control limit
limit
below the center line as you can see here
here
there is a three sigma or three standard division
division
in terms of the process variation distance
distance
from the center line upward and the
center line downward
the line above the center line is called
the upper control limit while the line
below the center line is called
the lower control limit in statistics
it is said that if a process follows a
normal distribution
all of the plotted points should fall inside
inside
what we call the plus 3 minus 3 sigma
or control limits this means
that the process is within statistical
process control
and if you talk about common causes of
variation this talks about
randomness we have data points inside
these control limits
and we can't figure out why is it there
meaning it's random now when there
are points that falls beyond the control limits
limits
just like this points it signals
the presence of what we call a special cause
cause
of variation meaning there is a reason
why these points are now out of control
points or
oocp this will now trigger us to investigate
investigate
our process and eventually identify
the reasons or causes of why we have
special causes of variation this is the
beauty of control chart
in action moving forward we will still
study what are the different type of
control charts
Click on any text or timestamp to jump to that moment in the video
Share:
Most transcripts ready in under 5 seconds
One-Click Copy125+ LanguagesSearch ContentJump to Timestamps
Paste YouTube URL
Enter any YouTube video link to get the full transcript
Transcript Extraction Form
Most transcripts ready in under 5 seconds
Get Our Chrome Extension
Get transcripts instantly without leaving YouTube. Install our Chrome extension for one-click access to any video's transcript directly on the watch page.
