Bioequivalence and Bioavailability Forum • ISC and Wilcoxon signed rank test

ISC and Wilcoxon signed rank test [Nonparametrics]

posted by d_labes – Berlin, Germany, 2017-01-04 11:21 (2662 d 10:47 ago) – Posting: # 16927
Views: 9,955

Dear mittyri,

❝ Could you please enlighten my pea-sized brain:

❝

❝ ❝ Method 1:

❝ ❝ Calculate the differences T-R for each subject and do a Wilcoxon signed rank test with these intra-subject differences

❝ For each subject we got one difference (contrast). How to perform the test using only one value for each subject?

Don't get your point.

May be you are confused by my writing

❝ ❝ Calculate the differences T-R for each subject

Sorry. But I'm not an English man (but only "een Balina, wa"). One difference for each subject, calculated as above described and analyzed by a Wilcoxon signed rank test (non-parametric analogue of a paired t-test) using of course the intra-subject contrasts of all subjects under study.

Let's take a hypothetical example, 8 subjects, ISC already calculated:


subj <- c(1,   2,    3,    4,   5,   6,     7,    8)

isc  <- c(0, 0.5, -0.5, 0.25, 0.0, 1.0, -0.25, -1.0)

tr <- wilcox.test(isc, conf.int = T, conf.level = 0.9, exact=F)

tr$estimate is the point estimate of T-R, tr$conf.int its 90% confidence interval.

exact=F is to avoid warnings

cannot compute exact p-value with ties

cannot compute exact p-value with zeroes

If you are interested in an exact solution wich can handle ties and zero's see package exactRankTests or coin.

—
Regards,

Detlew

Complete thread:

Tmax in Partial Replicate Design Joshua 2012-01-17 06:59 [Nonparametrics]
- Good question! Helmut 2012-01-17 11:34
  - Good question! Joshua 2012-01-20 11:54
    - Early exposure (+scaling?) Helmut 2012-01-20 12:56
- Tmax in Partial replicate design d_labes 2012-01-20 11:12
  - Tmax in Partial replicate design Joshua 2012-01-20 12:09
    - Intra-subject contrast (difference) d_labes 2012-01-20 12:55
      - Intra-subject contrast (difference) Joshua 2012-01-20 13:01
      - Wilcoxon for 2x2x4. "Not many things easier than that"? Astea 2023-02-14 18:44
  - Tmax in Partial replicate design mittyri 2017-01-03 23:24
    - ISC and Wilcoxon signed rank testd_labes 2017-01-04 10:21
      - ISC and Wilcoxon signed rank test in coin package mittyri 2017-01-04 14:17
        
        ISC and Wilcoxon signed rank test in coin package d_labes 2017-01-04 16:09