Dear Mr.Torsten: At Wed, 16 Jun 2004 08:04:08 +0200 (CEST), Torsten Hothorn wrote: > > Call: > > simtest.formula(formula = y4 ~ f2, data = dat2, type = "Dunnett") > > > > Dunnett contrasts for factor f2 > > > > Contrast matrix: > > f21 f22 f23 f24 f25 > > f22-f21 0 -1 1 0 0 0 > > f23-f21 0 -1 0 1 0 0 > > f24-f21 0 -1 0 0 1 0 > > f25-f21 0 -1 0 0 0 1 > > > > > > Absolute Error Tolerance: 0.001 > > > > Coefficients: > > Estimate t value Std.Err. p raw p Bonf p adj > > f25-f21 5.167 -4.644 1.022 0.000 0.000 0.000 > > f23-f21 2.875 -2.813 1.022 0.008 0.024 0.022 > > f24-f21 2.625 -2.569 1.022 0.015 0.029 0.028 > > f22-f21 2.125 -2.079 1.113 0.045 0.045 0.045 > > --------------------------------- > > Chihiro, > > Frank and I used your data to check the program and example with an > independent > algorithm and implementation (Westfall-Young stepdown resampling > procedure). Theory suggests that the > results should be similar to (but not necessarily the same as) those > obtained with multcomp in this special case. These are the adjusted > p-values obtained with the Westfall-Young approach for 100,000 > replications: > > which fit nicely with the ones obtained from multcomp. > > Hope this helps & sorry for the delay,
Thank you. At Mon, 07 Jun 2004 12:14:26 +0900, myself-oak wrote: > dunnett(dat2,1,2) > rho=0.426 > group:5 t=4.644 p=0.000 > group:3 t=2.813 p=0.028 > group:4 t=2.569 p=0.051 --- (B) > group:2 t=2.079 p=0.145 > (sorted in order of p values.) > > p values are different although t values are equal. > > > > I got the following inequality from the appended chart of a > > > book. > > > > > > > hm, without knowing what > > > > > 2.558 < d(5, 35, 0.4263464, 0.05) < 2.598 > > > > means it is hard to tell what the problem is. Could you please explain it > > further? > > The alternative hypothesis is "two sided". > > When significant level is equal to 0.05 , number of groups=5, > df of error=35 and rho=0.426, I think that absolute t-value > should be between 2.558 and 2.598. > > So, (B) is easy to understand for me than (A). You said "adj p" values are ... > 0.0437 > 0.0260 > 0.0204 > 0.0001 I used SPSS ver.10 and got the following result. Dunnett t (two sided) | --------------- | ---------- | -------- | -------- | ------------------ | | | mean diff. | s.e. | adj p | 95% C.I. | | ------ | ------ | (I-J) | | | ---------- | ----- | | (I) V3 | (J) V3 | | | | | | | ------ | ------ | ---------- | -------- | -------- | ---------- | ----- | | 2 | 1 | 2.125 | 1.022 | .145 | -.507 | 4.757 | | ------ | ------ | ---------- | -------- | -------- | ---------- | ----- | | 3 | 1 | 2.875(*) | 1.022 | .028 | .243 | 5.507 | | ------ | ------ | ---------- | -------- | -------- | ---------- | ----- | | 4 | 1 | 2.625 | 1.022 | .051 | -7.325E-03 | 5.257 | | ------ | ------ | ---------- | -------- | -------- | ---------- | ----- | | 5 | 1 | 5.167(*) | 1.113 | .000 | 2.301 | 8.032 | | ------ | ------ | ---------- | -------- | -------- | ---------- | ----- | I might make a mistake in the way to use the simtest()...How should I think? Best regards, -- kuroki GnuPG fingerprint = 90FD FE79 905F 26F9 29C4 096F 8AA2 2C42 5130 1469 ______________________________________________ [EMAIL PROTECTED] mailing list https://www.stat.math.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html
