This page collects some plots of the Gamma distribution. The plots help us to understand how the shape of the Gamma distribution changes when its parameters are changed.
The following plot contains the graphs of two Gamma
probability density functions. The first graph
(blue line) is the probability density function of a Gamma random variable
with
degrees of freedom and mean
.
The second graph (red line) is the probability density function of a Gamma
random variable with
degrees of freedom and mean
.
As
in both cases, the two distributions have the same mean. However, increasing
the number of degrees of freedom from
to
changes the shape of the distribution (the more the degrees of freedom are
increased the more the distribution resembles a normal distribution). The thin
vertical lines indicate the means of the two
distributions.
The following plot contains the graphs of two Gamma probability density
functions. The first graph (blue line) is the probability density function of
a Gamma random variable with
degrees of freedom and mean
.
The second graph (red line) is the probability density function of a Gamma
random variable with
degrees of freedom and mean
.
As
in both cases, the two distributions have the same mean. However, increasing
the number of degrees of freedom from
to
changes the shape of the distribution (the more the degrees of freedom are
increased the more the distribution resembles a normal distribution). The thin
vertical lines indicate the means of the two distributions.
The following plot contains the graphs of two Gamma probability density
functions. The first graph (blue line) is the probability density function of
a Gamma random variable with
degrees of freedom and mean
.
The second graph (red line) is the probability density function of a Gamma
random variable with
degrees of freedom and mean
.
Increasing the parameter
changes the mean of the distribution (from
to
).
However, the two distributions have the same number of degrees of freedom
(
).
Therefore, they have the same shape (one is the 'stretched version of the
other' - it would look exactly the same on a different scale). The thin
vertical lines indicate the means of the two distributions.
The following plot contains the graphs of two Gamma probability density
functions. The first graph (blue line) is the probability density function of
a Gamma random variable with
degrees of freedom and mean
.
The second graph (red line) is the probability density function of a Gamma
random variable with
degrees of freedom and mean
.
Increasing the parameter
changes the mean of the distribution (from
to
).
However, the two distributions have the same number of degrees of freedom
(
).
Therefore, they have the same shape (one is the 'stretched version of the
other' - it would look exactly the same on a different scale). The thin
vertical lines indicate the means of the two distributions.