It is a mathematical
tool/instrument that represents
a study characteristic of an
observable object that can
change
Types of statistical variables
Ordinal or
scale
variable
the data are “words”
that maintain a
“natural” order among
themselves.
Nominal
variable
the data are "words"
that do not keep
any "natural" order
between them
Discrete
Numeric
Variable
Data is “counting” quantities,
whole units.
Interval
variable:
the data measures “continuous”
magnitudes (such as times,
distances, etc.), which admit
intermediate values (with
decimals)
Herramients
histogram
Quality professionals are often tasked with
analyzing and interpreting the behavior of
different sets of data in an effort to manage
quality. This is where quality control tools like
the histogram come into play
Ishikawa's diagram
The fishbone diagram helps users identify
the various factors (or causes) that lead to
an effect, usually described as a problem to
be solved. Named for its resemblance to a
fish bone
data collection sheet
When used to collect quantitative data, they
may be referred to as a tally sheet. A check sheet
collects data in the form of check marks or
counts that indicate how many times a particular
value has occurred
Pareto chart
As a quality control tool, the Pareto chart operates
according to the 80-20 rule. This rule assumes that
in any process, 80% of the problems of a process or
system are caused by the top 20% of the factors.
control chart
Quality improvement can help quality assurance
professionals determine whether or not a
process is stable and predictable, making it
easier to identify factors that can lead to
variances or defects.
Dispersion diagram
the scatterplot is most useful for depicting the
relationship between two variables, which is
ideal for quality assurance professionals trying
to identify cause-and-effect relationships
importance
It has become an important tool in research processes,
since it allows planning research, collecting, organizing,
representing, interpreting and analyzing information
regarding individuals or observations.