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RegisterInter and Total Variability [Power / Sample Size]
posted by Helmut 
– Vienna, Austria, 2011-09-14 02:43 (5047 d 04:36 ago) – Posting: # 7351
Views: 13,740
Dear Benjamin,
THX for thinking it over again and forcing me to dig out old references. My output (given by a software I have written in the mid-1980s) didn’t contain MSEt (only SSEt and df). In this table I thoughtlessly used MSEt = SSEt/df…
Which reduces to MSEt = (MSEB + MSEW)/2. q.e.d.
I should have paid more attention to my own slide.
Therefore:
The percentage CVtotal intra/total is nonsense (apples and oranges).
Right.
Also correct. But then we are relying on:
![[image]](img/uploaded/image12.jpg)
In the methylphenidate example conservatism will be very expensive.
THX for thinking it over again and forcing me to dig out old references. My output (given by a software I have written in the mid-1980s) didn’t contain MSEt (only SSEt and df). In this table I thoughtlessly used MSEt = SSEt/df…
❝ […] MSEt is not the sum of MSEw and MSEB, it's MSEw + (MSEB - MSEW)/2.
Which reduces to MSEt = (MSEB + MSEW)/2. q.e.d.
I should have paid more attention to my own slide.
Therefore:
Study CVintra CVinter CVtotal MSEw MSEB MSEt
Methylphenidate 7.00% 19.13% 20.41% 0.004882 0.076746 0.040814
Lansoprazole 47.01% 25.14% 54.60% 0.199667 0.322229 0.260948The percentage CVtotal intra/total is nonsense (apples and oranges).
❝ And σ²inter is estimated by (MSEB - MSEW)/2 and not MSEB (in the references you posted these values are plugged in for calculating the corresponding CV, so I guess these values themselves represent direct estimates for the variances).
Right.
❝ Then of course it makes sense. A conservative estimator for the intra variability would then be MSE_t.
Also correct. But then we are relying on:
In the methylphenidate example conservatism will be very expensive.
—
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Helmut Schütz
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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:
- Inter and Total Variability Ben 2011-09-02 13:43 [Power / Sample Size]
![[Mix]](https://static.bebac.at/img/mix.png "open in Mix view")
- Inter and Total Variability Helmut 2011-09-02 14:21
- Inter and Total Variability Ben 2011-09-03 11:28
- Inter and Total Variability Ben 2011-09-08 19:22
- Inter and Total Variability Helmut 2011-09-11 11:55
- Inter and Total Variability Ben 2011-09-13 22:03
- Inter and Total VariabilityHelmut 2011-09-14 00:43
- Inter and Total Variability Ben 2011-09-18 12:36
- Inter and Total Variability Ben 2011-10-06 18:51
- Inter-subject variance sasophylistic (GLM vs. MIXED) d_labes 2011-10-07 13:33
- Inter and Total VariabilityHelmut 2011-09-14 00:43
- Inter and Total Variability Ben 2011-09-13 22:03
- Inter and Total Variability ElMaestro 2011-09-18 14:14
- Inter and Total Variability Ben 2011-09-19 19:43
- Inter and Total Variability Helmut 2011-09-11 11:55
- Inter and Total Variability Ben 2011-09-08 19:22
- Inter and Total Variability Ben 2011-09-03 11:28
- Inter and Total Variability Helmut 2011-09-02 14:21
Ing. Helmut Schütz