variability

1. SCRIPT FOR THE VIDEO
Whe are studentsof the Technological University of Torreon
We´re going to talk about the statistics variability
My partner: Elizabeth grijalbarocha
And servant =: Karen lizethbarajasalmeida
What is varability?
Variability occurs variables that can be desive to achieve the required
quality.processes generally use diferentresarces in order to produce products
Or services.
How many types of variability are there?
Three types of variability.
Variability systematic and planned.Typical variability problem and the nature of the
experiment.Systematic variability and unplanned.
What are the security measures?
Variability measures are designed to measure the magnitude of the deviations of
the values of the variable with respect to the central value of the distribution.

2. What is the purpose of the measures of variability?
Accurately calculate measures of variability such as variance and standard
deviation.
What is the coefficient of variation?
The coefficient of variation at different scales but are correlated statistically and
substantively with one common factor. That is, both variables have a causal
relationship with this factor.
Rule Description Chart Example Problem Indicated

3. One sample (two
One point is more than
Rule shown in this case)
3 standard deviations
1 is grossly out of
from the mean.
control.
Nine (or more) points
Rule Some prolonged
in a row are on the
2 bias exists.
same side of the mean.
Six (or more) points in
Rule a row are continually
A trend exists.
3 increasing (or
decreasing).

4. This much
oscillation is beyond
Fourteen (or more) noise.
points in a row
Rule
alternate in direction, This is directional
4
increasing then and the position of
decreasing. the mean and size of
the standard
deviation do not
affect this rule.
There is a medium
tendency for
Two (or three) out of samples to be
three points in a row mediumly out of
Rule are more than 2 control.
5 standard deviations
from the mean in the
same direction. The side of the
mean for the third
point is unspecified.
There is a strong
tendency for
Four (or five) out of samples to be
five points in a row are slightly out of
Rule more than 1 standard control.
6 deviation from the
mean in the same
direction. The side of the
mean for the fifth
point is unspecified.
Fifteen points in a row
With 1 standard
are all within 1
Rule deviation, greater
standard deviation of
7 variation would be
the mean on either side
expected.
of the mean.

5. Eight points in a row
Jumping from above
exist with none within
to below whilst
1 standard deviation of
Rule missing the first
the mean and the
8 standard deviation
points are in both
band is rarely
directions from the
random
mean.
WESTERN ELECTRIC RULE
Rule Description Chart Example
Any single data point falls outside the 3standard
Rule 1 deviations limit from the centerline (i.e., any point
that falls outside Zone A, beyond either the upper
or lower control limit)
Two out of three consecutive points fall beyond
Rule 2 the 2σ limit (in zone A or beyond), on the same
side of the centerline

6. Four out of five consecutive points fall beyond the
Rule 3 1σ limit (in zone B or beyond), on the same side of
the centerline
Nineconsecutive points fall on the same side of
Rule 4 the centerline (in zone C or beyond)
BIBLIOGRAPHY:
 books.google.com.mxAlberto Luceño Vazquez, Francisco Javier Gonzalez, Francisco Javier
Gonzalez Ortiz, Marta Pascual Saez, Jose Maria Sarabia Joy, Alberto Luceño Vazquez,
Francisco Javier Gonzalez - 2005 - 338 pages.
 books.google.com.mxAlbert Bartes Prat, Xavier Tort-Martorell Llabrés, Pere Grima Cintas -
2004 - 376 pages.
 books.google.com.mxWilliam Mendenhall - 2007 - 776 pages.
 books.google.com.mxRobert Johnson, Patricia Kuby - 2003 - 509 pages.
 books.google.com.mxJay L. Devore - 2008 - 744 pages.