Colin
You need to bear in mind that statistical tests such
as t and F are only testing a very simple hypothesis -
they do not test whether the samples are from the same
population.
The F test is to check whether the standard deviations
differ. If the ore is from the same genesis, it is
likely tha
Hence my recommendation to use cross cross validation
Isobel
http://geoecosse.bizland.com/books.htm
--- Colin Daly <[EMAIL PROTECTED]> wrote:
>
>
> Hi
>
> Sorry to repeat myself - but the samples are not
> independent. Independance is a fundamental
> assumption of these types of tests - an
There ws a pretty good paper on global standard errors
in the 1984 APCOM proceedings, so I am sure it should
be in the major textbooks by now.
Commparing the sills is very straightforward, I think.
Isobel
http://geecosse.bizland.com/books.htm
--- Chaosheng Zhang <[EMAIL PROTECTED]>
wrote:
> Is
RE : "F and T tests"
One should be careful in simply referring to "F and T tests". There is
no such thing as a uniquely identified/determined "F test" nor a
uniquely identified/determined "T test". In both cases one is simply
identifying the distribution of a test statistic.
The F distri
TED]>
Cc: <[EMAIL PROTECTED]>
Sent: Monday, December 06, 2004 6:03 PM
Subject: [ai-geostats] Re: F and T-test for samples drawn from the same p
> There ws a pretty good paper on global standard errors
> in the 1984 APCOM proceedings, so I am sure it should
> be in the majo
While your talking about sill's being the global variance which I read
everywhere,
isn't the global variance actually slightly less than the sill, as the
values below the
range of the variogram are not included? i.e. the sill would be the global
variance
when you have pure nugget effect.
* By
Digby
I see where you are coming from on this, but in fact
the sill is composed of those pairs of samples which
are independent of one another - or, at least, have
reached some background correlation. This is why the
sill makes a better estimate of the variance than the
conventional statistical me
Hi Isobel,
Could you explain why it would be a better estimate of the variance when
independance is considered? I'd rather think that we consider the
dependance when the overall variance are to be estimated-- if there
actually is dependance between values.
Or are you talking about modeling sill v
