In: Statistics and Probability
Let π1, π2,β¦, ππ be a random sample of a gamma distribution with parameters πΌ (known) and π½ (unknown), prove that π (πΏ) = πΜ is a sufficient estimator for π½.
Let
be a random sample from the pdf or pmf
. Then the statistics
is sufficient for
, iff we can factorize the joint PDF and PMF of
as
Where
depends on
but not on
and
depends on
and on
only through
Join density function is given by:
Now let,
Cleraly
depends on
but not on
But
depends depends on
and on
only through
Hence factorization theorem implies
is sufficient Statistics for estimator