EXPONENTIAL FAMILY & GLMS
Three components required for GLM
Response variables Y, Yn assumed be from a distribution
1. . .
.,
to
belonging to the
exponential family
. A
2 set of parameters B and explanatory variables si for i= 1 ,2
, ...,
N
. A
3 monotone link function g) such that g(mi)-ociTB for i= 1, 2
, ...,
N
Exponential family parameter of interest
f(y : 2) =
exp(a(y)b(z) + c(q) +
d(y)
·
aly) y - = canonical form
·
bla) is the natural parameter
mean and Variance
(2)
E(a(y))
-
=
D'(8)
C'(G)b"(a) -
C"(2)b'(G)
var(a(y)) =
(b'(2))3
Likelihood function
e(y ; 8) =
a(y)b(a) + c(a) +
d(y)
e'(y : 2) =
a(y)b'(z) +
c'(2)
e"(yiz) =
a(y)b"(2) + c"(2)
Score function
U(aiy) G = =
a(y)b'(a) + C'(2) function
U =
a(Y)b' (2) + c' (2) statistic
E(U) =
b'(G)E(a(y)] + c'(z)
=-
D'Ac
E(U] =
0
var(u] =
E(u2) -
E(u) =
E(Un
var(u) =
-
f(u) = Y
-
E(U) =
b"(8)f(a(Y)] -
c"(2)
-
Cable
Y =
(b'(a)) Var(a(y)]
,
Three components required for GLM
Response variables Y, Yn assumed be from a distribution
1. . .
.,
to
belonging to the
exponential family
. A
2 set of parameters B and explanatory variables si for i= 1 ,2
, ...,
N
. A
3 monotone link function g) such that g(mi)-ociTB for i= 1, 2
, ...,
N
Exponential family parameter of interest
f(y : 2) =
exp(a(y)b(z) + c(q) +
d(y)
·
aly) y - = canonical form
·
bla) is the natural parameter
mean and Variance
(2)
E(a(y))
-
=
D'(8)
C'(G)b"(a) -
C"(2)b'(G)
var(a(y)) =
(b'(2))3
Likelihood function
e(y ; 8) =
a(y)b(a) + c(a) +
d(y)
e'(y : 2) =
a(y)b'(z) +
c'(2)
e"(yiz) =
a(y)b"(2) + c"(2)
Score function
U(aiy) G = =
a(y)b'(a) + C'(2) function
U =
a(Y)b' (2) + c' (2) statistic
E(U) =
b'(G)E(a(y)] + c'(z)
=-
D'Ac
E(U] =
0
var(u] =
E(u2) -
E(u) =
E(Un
var(u) =
-
f(u) = Y
-
E(U) =
b"(8)f(a(Y)] -
c"(2)
-
Cable
Y =
(b'(a)) Var(a(y)]
,