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r2

R2 or r2 is a label used in different domains to denote distinct concepts. This article outlines the main senses in mathematics, statistics, and popular culture, among others.

In mathematics, R2 typically refers to the two-dimensional real Euclidean space, written as R^2 in formal notation.

In statistics and data analysis, R-squared, often abbreviated as r^2, is a measure of how well a

In popular culture, R2-D2 is a fictional astromech droid in the Star Wars franchise. The character is

Other uses of the term appear in various technical and colloquial contexts, often as a shorthand for

It
is
the
Cartesian
plane
consisting
of
all
pairs
of
real
numbers
(x,
y).
R^2
underpins
planar
geometry
and
analytic
methods,
with
distances
and
angles
measured
by
the
Euclidean
metric:
d((x1,y1),(x2,y2))
=
sqrt((x1−x2)^2+(y1−y2)^2).
Points,
vectors,
and
functions
in
the
plane
are
commonly
represented
within
this
space.
model
explains
observed
variation.
It
is
defined
as
1
minus
the
ratio
of
the
residual
sum
of
squares
to
the
total
sum
of
squares
(r^2
=
1
−
SS_res/SS_tot).
R^2
values
range
from
0
to
1,
with
higher
values
indicating
a
better
fit
for
linear
models.
Adjusted
R^2
modifies
this
metric
to
account
for
the
number
of
predictors
in
a
model
and
is
used
to
compare
models
more
fairly.
known
for
its
distinctive
beeps,
loyal
service
aboard
starships,
and
role
in
navigation
and
maintenance
tasks.
squared
quantities
or
second
components.
The
intended
meaning
of
r2
depends
on
the
field
and
the
surrounding
information.