This page collects some plots of the Student's t distribution. The plots help us to understand how the shape of the distribution changes when a parameter is changed.
The following plot contains the graphs of two Student's t
probability density functions. The first graph
(blue line) is the probability density function of a Student's t random
variable with parameters
,
and
.
The second graph (red line) is the probability density function of a Student's
t random variable with parameters
,
and
.
Changing the mean from
to
,
the shape of the graph does not change, but the graph is translated to the
right (its location changes).
The following plot contains the graphs of two Student's t probability density
functions. The first graph (blue line) is the probability density function of
a Student's t random variable with parameters
,
and
.
The second graph (red line) is the probability density function of a Student's
t random variable with parameters
,
and
.
Changing the scale parameter from
to
,
the location of the graph does not change (it remains centered at
),
but the shape of the graph changes (there is less density in the center and
more density in the tails).
The following plot contains the graphs of two Student's t probability density
functions. The first graph (blue line) is the probability density function of
a Student's t random variable with parameters
,
and
.
The second graph (red line) is the probability density function of a Student's
t random variable with parameters
,
and
.
Increasing the number of degrees of freedom from
to
,
the location of the graph does not change (it remains centered at
)
and its shape changes only marginally (the tails become thinner).