## Some answers [Two-Stage / GS Designs]

I’m in a hurry; so answering only part of your questions (leave the others to Detlew or Ben).

❝ 2. Why did you decide to include CI futility rule by default?

This applies only to the

`x.tsd.in`

functions (to be in accordance with the paper of Maurer *et al.*).

❝ 3. Regarding your flowchart:

❝ isn't it possible that we get some value lower than 4?

❝ for example and after first stage CV=15%, CI=[0.7991897 1.0361745]:

❝ `sampleN2.TOST(CV=0.15, n1=12)`

```
❝ Design alpha CV theta0 theta1 theta2 n1 Sample size
```

❝ 2x2 0.0294 0.15 0.95 0.8 1.25 12 2

`sampleN2.TOST()`

is intended for the other methods where at the end stages are pooled.In the inverse normal method stages are evaluated

*separately*(PE and MSE from ANOVAS of each stage). If you have less than 4 subjects in the second stage you will run out of steam (too low degrees of freedom). Well, 3 would work, but…

❝ 5. I was confused with "2stage" 'aliased' with "tsd" and was looking for differences some time

❝ Are there any reasons to double that functions?

Since this is a

**0**.x-release according to CRAN’s policy we can rename functions or even remove them

*without*further notice.

_{}We decided to unify the function-names. In order not to break existing code we introduced the aliases. In the next release functions

`x.2stage.x()`

will be removed and only their counterparts `x.tsd.x()`

kept.❝ regarding 3rd point:

❝ I tried

❝ `interim.tsd.in(GMR1=sqrt(0.7991897 * 1.0361745), CV1=0.15,n1=12, fCrit="No")`

`❝ […]`

```
```

❝ - Calculated n2 = 4

`❝ - Decision: Continue to stage 2 with 4 subjects`

❝ oh, there's a default argument min.n2 = 4

❝ OK, let's try to change that:

❝ `interim.tsd.in(GMR1=sqrt(0.7991897 * 1.0361745), CV1=0.15,n1=12, fCrit="No", min.n2 = 2)`

`❝ Error in interim.tsd.in(GMR1 = sqrt(0.7991897 * 1.0361745), CV1 = 0.15, :`

```
❝ min.n2 has to be at least 4.
```

❝ Why couldn't I select a smaller one?

See above. Doesn’t make sense with zero degrees of freedom (n

_{2}=2).

*Dif-tor heh smusma*🖖🏼 Довге життя Україна!

_{}

Helmut Schütz

The quality of responses received is directly proportional to the quality of the question asked. 🚮

Science Quotes

### Complete thread:

- Finally: Exact TSD methods for 2×2 crossover designs Helmut 2018-04-21 17:17 [Two-Stage / GS Designs]
- Exact TSD methods: Example Helmut 2018-04-21 20:33
- Finally: Exact TSD methods for 2×2 crossover designs ElMaestro 2018-04-21 20:49
- Flow chart (without details) Helmut 2018-04-21 21:41
- naive questions regarding new functions in Power2Stage mittyri 2018-04-28 15:54
- Some answersHelmut 2018-04-28 17:29
- Some more "answers" d_labes 2018-04-29 21:11
- clarification regarding user Power2Stage guides mittyri 2018-04-30 13:41

- naive questions regarding new functions in Power2Stage mittyri 2018-04-28 15:54

- Flow chart (without details) Helmut 2018-04-21 21:41
- Technicality: Weigths for the inverse normal approach d_labes 2018-04-25 14:19
- Selection of w and w* Helmut 2018-04-26 09:51
- Selection of w and w* d_labes 2018-04-26 20:02
- Now what? w & w* examples d_labes 2018-05-09 13:53
- Now what? w & w* examples Ben 2018-06-10 20:12
- Now what? w & w* examples Helmut 2018-06-11 13:57
- Now what? w & w* examples Ben 2018-06-12 19:14

- a bug in interim.tsd.in()? mittyri 2018-06-11 23:27
- a bug in interim.tsd.in()? Ben 2018-06-12 19:32
- Nonbinding futility rule d_labes 2018-06-13 16:59
- Bad weather? Helmut 2018-06-13 19:23
- NLYW? d_labes 2018-06-14 10:18

- Nonbinding futility rule Ben 2018-06-13 20:26
- Nonbinding futility rule d_labes 2018-06-14 10:47
- Nonbinding futility rule Ben 2018-06-15 17:58
- Binding / Nonbinding futility rule - alpha control d_labes 2018-06-16 19:42
- Binding / Nonbinding futility rule - alpha control Ben 2019-03-30 09:52

- Binding / Nonbinding futility rule - alpha control d_labes 2018-06-16 19:42

- Nonbinding futility rule Ben 2018-06-15 17:58

- Nonbinding futility rule d_labes 2018-06-14 10:47

- Bad weather? Helmut 2018-06-13 19:23

- Nonbinding futility rule d_labes 2018-06-13 16:59

- a bug in interim.tsd.in()? Ben 2018-06-12 19:32

- Now what? w & w* examples Helmut 2018-06-11 13:57

- Now what? w & w* examples Ben 2018-06-10 20:12

- Selection of w and w* Helmut 2018-04-26 09:51