<s>
A	O
data	B-General_Concept
set	I-General_Concept
(	O
or	O
dataset	B-General_Concept
)	O
is	O
a	O
collection	O
of	O
data	O
.	O
</s>
<s>
In	O
the	O
case	O
of	O
tabular	O
data	O
,	O
a	O
data	B-General_Concept
set	I-General_Concept
corresponds	O
to	O
one	O
or	O
more	O
database	B-Application
tables	I-Application
,	O
where	O
every	O
column	B-Application
of	O
a	O
table	O
represents	O
a	O
particular	O
variable	O
,	O
and	O
each	O
row	B-Application
corresponds	O
to	O
a	O
given	O
record	O
of	O
the	O
data	B-General_Concept
set	I-General_Concept
in	O
question	O
.	O
</s>
<s>
The	O
data	B-General_Concept
set	I-General_Concept
lists	O
values	O
for	O
each	O
of	O
the	O
variables	O
,	O
such	O
as	O
for	O
example	O
height	O
and	O
weight	O
of	O
an	O
object	O
,	O
for	O
each	O
member	O
of	O
the	O
data	B-General_Concept
set	I-General_Concept
.	O
</s>
<s>
Data	B-General_Concept
sets	I-General_Concept
can	O
also	O
consist	O
of	O
a	O
collection	O
of	O
documents	O
or	O
files	O
.	O
</s>
<s>
In	O
the	O
open	O
data	O
discipline	O
,	O
data	B-General_Concept
set	I-General_Concept
is	O
the	O
unit	O
to	O
measure	O
the	O
information	O
released	O
in	O
a	O
public	O
open	O
data	O
repository	O
.	O
</s>
<s>
The	O
European	O
data.europa.eu	O
portal	O
aggregates	O
more	O
than	O
a	O
million	O
data	B-General_Concept
sets	I-General_Concept
.	O
</s>
<s>
Some	O
other	O
issues	O
(	O
real-time	B-General_Concept
data	I-General_Concept
sources	I-General_Concept
,	O
non-relational	B-General_Concept
data	B-General_Concept
sets	I-General_Concept
,	O
etc	O
.	O
)	O
</s>
<s>
Several	O
characteristics	O
define	O
a	O
data	B-General_Concept
set	I-General_Concept
's	O
structure	O
and	O
properties	O
.	O
</s>
<s>
These	O
include	O
the	O
number	O
and	O
types	O
of	O
the	O
attributes	O
or	O
variables	O
,	O
and	O
various	O
statistical	O
measures	O
applicable	O
to	O
them	O
,	O
such	O
as	O
standard	B-General_Concept
deviation	I-General_Concept
and	O
kurtosis	B-Error_Name
.	O
</s>
<s>
In	O
statistics	O
,	O
data	B-General_Concept
sets	I-General_Concept
usually	O
come	O
from	O
actual	O
observations	O
obtained	O
by	O
sampling	O
a	O
statistical	O
population	O
,	O
and	O
each	O
row	B-Application
corresponds	O
to	O
the	O
observations	O
on	O
one	O
element	O
of	O
that	O
population	O
.	O
</s>
<s>
Data	B-General_Concept
sets	I-General_Concept
may	O
further	O
be	O
generated	O
by	O
algorithms	O
for	O
the	O
purpose	O
of	O
testing	O
certain	O
kinds	O
of	O
software	O
.	O
</s>
<s>
Some	O
modern	O
statistical	O
analysis	O
software	O
such	O
as	O
SPSS	B-Algorithm
still	O
present	O
their	O
data	O
in	O
the	O
classical	O
data	B-General_Concept
set	I-General_Concept
fashion	O
.	O
</s>
<s>
If	O
data	O
is	O
missing	O
or	O
suspicious	O
an	O
imputation	B-General_Concept
method	O
may	O
be	O
used	O
to	O
complete	O
a	O
data	B-General_Concept
set	I-General_Concept
.	O
</s>
<s>
Several	O
classic	O
data	B-General_Concept
sets	I-General_Concept
have	O
been	O
used	O
extensively	O
in	O
the	O
statistical	O
literature	O
:	O
</s>
<s>
Iris	B-Language
flower	I-Language
data	I-Language
set	I-Language
–	O
Multivariate	O
data	B-General_Concept
set	I-General_Concept
introduced	O
by	O
Ronald	O
Fisher	O
(	O
1936	O
)	O
.	O
</s>
<s>
Categorical	O
data	O
analysis	O
–	O
Data	B-General_Concept
sets	I-General_Concept
used	O
in	O
the	O
book	O
,	O
An	O
Introduction	O
to	O
Categorical	O
Data	O
Analysis	O
.	O
</s>
<s>
Robust	O
statistics	O
–	O
Data	B-General_Concept
sets	I-General_Concept
used	O
in	O
Robust	O
Regression	O
and	O
Outlier	O
Detection	O
(	O
Rousseeuw	O
and	O
Leroy	O
,	O
1968	O
)	O
.	O
</s>
