p
a
r
a
m
e
t
e
r
λ
1
.
m
e
a
n
:
1
λ
=
1
.
0
0
0
v
a
r
i
a
n
c
e
:
1
2
λ
=
1
.
0
0
0
m
o
m
e
n
t
g
e
n
e
r
a
t
i
n
g
f
u
n
c
t
i
o
n
:
λ
λ
-
t
=
1
.
1
.
-
t