If my usage is wrong please correct me. Thank you. Here are my reason :
1. p-value is a (cumulative) probability and always ranges from 0 to 1. A test statistic depending on its definition can wider range of possible values. 2. A test statistics is one that is calculated from the data without the need of assuming a null distribution. Whereas to calculate p-values, you need to assume a null distribution or estimate it empirically using permutation techniques. 3. The directionality of a test statistics may be ignored. For example a t-statistics of -5 and 5 are equally interesting in a two-sided testing. But the smaller the p-value, more evidence against the null hypothesis. Regards, Adai On Thu, 2005-11-10 at 06:05 -0500, Duncan Murdoch wrote: > On 11/9/2005 10:01 PM, Adaikalavan Ramasamy wrote: > > I think an alternative is to use a p-value from F distribution. Even > > tough it is not a statistics, it is much easier to explain and popular > > than 1/F. Better yet to report the confidence intervals. > > Just curious about your usage: why do you say a p-value is not a statistic? > > Duncan Murdoch > > > > > Regards, Adai > > > > > > > > On Wed, 2005-11-09 at 17:09 -0600, Mike Miller wrote: > > > >>On Wed, 9 Nov 2005, Gao Fay wrote: > >> > >> > >>>Hi there, > >>> > >>>Suppose mu is constant, and error is normally distributed with mean 0 and > >>>fixed variance s. I need to find a statistics that: > >>>Y_i = mu + beta1* I1_i beta2*I2_i + beta3*I1_i*I2_i + +error, where I_i is > >>>1 > >>>Y_i is from group A, and 0 if Y_i is from group B. > >>> > >>>It is large when beta1=beta2=0 > >>>It is small when beta1 and/or beta2 is not equal to 0 > >>> > >>>How can I find it by R? Thank you very much for your time. > >> > >> > >>That's a funny question. Usually we want a statistic that is small when > >>beta1=beta2=0 and large otherwise. > >> > >>Why not compute the usual F statistic for the null beta1=beta2=0 and then > >>use 1/F as your statistic? > >> > >>Mike > >> > >>______________________________________________ > >>R-help@stat.math.ethz.ch mailing list > >>https://stat.ethz.ch/mailman/listinfo/r-help > >>PLEASE do read the posting guide! > >>http://www.R-project.org/posting-guide.html > >> > > > > > > ______________________________________________ > > R-help@stat.math.ethz.ch mailing list > > https://stat.ethz.ch/mailman/listinfo/r-help > > PLEASE do read the posting guide! > > http://www.R-project.org/posting-guide.html > > ______________________________________________ R-help@stat.math.ethz.ch mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html