, 2005 7:39 pm
Subject: Re: [R] exact values for p-values - more information.
I just checked:
pf(39540, 1, 7025, lower.tail=FALSE, log.p=TRUE)
[1] -Inf
This is not correct. With 7025 denominator degrees of
freedom, we
might use the chi-square approximation
If they have the same degrees of freedom, use the test statistic
and not
the p value for comparing them.
Z
I appretiate your input to this discussion. Do you know of a reference
to your statement above?
I had actually used the test-statistic which in my case is r-squared
to compare them.
On Tue, 12 Jul 2005, S.O. Nyangoma wrote:
If they have the same degrees of freedom, use the test statistic
and not
the p value for comparing them.
Z
I appretiate your input to this discussion. Do you know of a reference
to your statement above?
?? Any basic statistics book?
Hi there,
If I do an lm, I get p-vlues as
p-value: 2.2e-16
This is obtained from F =39540 with df1 = 1, df2 = 7025.
Suppose am interested in exact value such as
p-value = 1.6e-16 (note = and not )
How do I go about it?
stephen
__
On Mon, 11 Jul 2005, S.O. Nyangoma wrote:
Hi there,
If I do an lm, I get p-vlues as
p-value: 2.2e-16
This is obtained from F =39540 with df1 = 1, df2 = 7025.
Suppose am interested in exact value such as
p-value = 1.6e-16 (note = and not )
How do I go about it?
You can always
I just checked:
pf(39540, 1, 7025, lower.tail=FALSE, log.p=TRUE)
[1] -Inf
This is not correct. With 7025 denominator degrees of freedom, we
might use the chi-square approximation to the F distribution:
pchisq(39540, 1, lower.tail=FALSE, log.p=TRUE)
[1]
Compare the following
t.test( 1:100, 101:200 )$p.value
t.test( 1:100, 101:200 )
In the latter, the print method truncates to 2.2e-16.
You can go as far as (depending on your machine)
.Machine$double.xmin
[1] 2.225074e-308
before it becomes indistinguishable from zero.
But there
an article using this method?
Regards. Stephen.
- Original Message -
From: Spencer Graves [EMAIL PROTECTED]
Date: Monday, July 11, 2005 7:39 pm
Subject: Re: [R] exact values for p-values - more information.
I just checked:
pf(39540, 1, 7025, lower.tail=FALSE, log.p=TRUE
: Monday, July 11, 2005 7:39 pm
Subject: Re: [R] exact values for p-values - more information.
I just checked:
pf(39540, 1, 7025, lower.tail=FALSE, log.p=TRUE)
[1] -Inf
This is not correct. With 7025 denominator degrees of
freedom, we
might use the chi-square approximation
