Suppose that we have a statistical model with
q unknown parameters
w, and an estimate
, based on a sample of size
n. A basic question is: what is the covariance of the estimate? The covariance is needed for the Central Limit Theorem (CLT). This gives a first approximation for the distribution of
. But what if
increases with
n? How fast can it increase and the CLT still hold? An answer has so far only been given for the sample mean. The same is true for the Edgeworth expansions. These are expansions in powers of
for the density and distribution of
. For fixed
q, these expansions are important, as they show how small
n can be for the CLT to apply. When it does, they can greatly improve the accuracy of the CLT. I give conditions that allow for the Edgeworth expansions to remain valid when
increases with
n. Earlier Edgeworth expansions when
increases, have only been done for a sample mean, and only for a 2nd order Edgeworth expansion. In contrast, I consider a very large class of estimates, the class of non-lattice standard estimates. An estimate is said to be a standard estimate if its mean converges to its true value as
n increases, and for
, its
rth order cumulants have magnitude
and can be expanded in powers of
. For this class of estimates, I show that the Edgeworth expansions hold if
grows as a power of
n less than
That is, I give these expansions in powers of
. This large class of estimates has a huge range of potential applications, as estimates of high dimension are common in nearly all areas of applied statistics. The most important type of standard estimate is when
is a smooth function of a sample mean, of dimension
p say. When either or both
and
increase with
n, I give conditions on their growth for the Edgeworth expansions for
to remain valid: the eighth power of
p times the sixth power of
q cannot grow as fast as
n. This holds for fixed
if
grows less than a power of
n less than
. This appears to be the first time when Edgeworth expansions have been given when not one, but two dimensions, are allowed to increase to
∞ with
n. This gives two different pathways for allowing an increase in dimensionality. When
, I give 5th order Edgeworth-Cornish-Fisher expansions for the standardized distribution and its quantiles of any smooth function of a sample mean of dimension
, when
is a power of
n less than
. However for the special case when this function is linear, there is no restriction whatever on how fast
can increase! If also the components of the sample mean are independent, then these expansions are in powers of
. I also give a method that greatly reduces the number of terms needed for the 2nd and 3rd order terms in the Edgeworth expansions, that is, for the 1st and 2nd order corrections to the CLTs. I also extend these results to the case where
is a function of several independent sample means, each of dimension increasing with
n, with total dimension
p.
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