On Wednesday 22 September 2004 13:07, Ted Harding wrote:
On 22-Sep-04 kan Liu wrote:
Hi, Many thanks for your helpful comments and suggestions. The attached
are the data in both log10 scale and original scale. It would be very
grateful if you could suggest which version of test should be
Hi Liu,
before applying a t-test (or any test) you should first check if the
assumptions of the test are supported by your data, i.e., in a t-test
x and y must be normally distributed.
I hope it helps.
Best,
Dimitris
Dimitris Rizopoulos
Ph.D. Student
Biostatistical Centre
School of Public
Hi Dimitris,
you are describing a more stringent requirement than the t-test
actually requires. It's the sampling distribution of the mean that
should be normal, and this condition is addressed by the Central
Limit Theorem.
Whether or not the CLT can be invoked depends on numerous factors,
Hi, Many thanks for your helpful comments and suggestions. The attached are the data
in both log10 scale and original scale. It would be very grateful if you could suggest
which version of test should be used.
By the way, how to check whether the variation is additive (natural scale) or
Hi, Many thanks for your helpful comments and suggestions.
You're welcome.
The attached are the data in both log10 scale and original scale. It
would be very grateful if you could suggest which version of test
should be used.
I feel that it would be inappropriate. It depends on the origin
120544.9 107909.0
-Original Message-
From: kan Liu [mailto:[EMAIL PROTECTED]
Sent: 22 September 2004 10:22
To: Andrew Robinson; Dimitris Rizopoulos
Cc: [EMAIL PROTECTED]
Subject: Re: [R] t test problem?
Hi, Many thanks for your helpful comments and suggestions. The attached
On 22-Sep-04 kan Liu wrote:
Hi, Many thanks for your helpful comments and suggestions. The attached
are the data in both log10 scale and original scale. It would be very
grateful if you could suggest which version of test should be used.
By the way, how to check whether the variation is
-Original Message-
From: kan Liu [mailto:[EMAIL PROTECTED]
Sent: 22 September 2004 10:22
To: Andrew Robinson; Dimitris Rizopoulos
Cc: [EMAIL PROTECTED]
Subject: Re: [R] t test problem?
Hi, Many thanks for your helpful comments and suggestions. The attached are the data
in both log10 scale
Kan Liu wrote:
Hello,
I got two sets of data
x=(124738, 128233, 85901, 33806, ...)
y=(25292, 21877, 45498, 63973, )
When I did a t test, I got two tail p-value = 0.117, which is not
significantly different.
If I changed x, y to log scale, and re-do the t test, I got two tail
p-value
