## Studentized & standardized residuals [Outliers]

Hi UdayK,

“Studentized residual” is an ambiguous term. There are two flavors:

Both are easily obtained in SAS, R,…

In R for the fixed effects model (untested!):

BTW,

❝ […] outlier test using Phoenix WinNonlin Software (Studentized residual method) and R-Software (code) in the Bioequivalence 2way cross design.

“Studentized residual” is an ambiguous term. There are two flavors:

*Internally*studentized (aka “standardized”), where

\(\widehat{\sigma}^2={1 \over n-m}\sum_{j=1}^n \widehat{\varepsilon\,}_j^{\,2}\)

*Externally*studentized, where

\(\widehat{\sigma}_{(i)}^2={1 \over n-m-1}\sum_{\begin{smallmatrix}j = 1\\j \ne i\end{smallmatrix}}^n \widehat{\varepsilon\,}_j^{\,2}\)

Both are easily obtained in SAS, R,…

In R for the fixed effects model (untested!):

`mod <- lm(log(PK) ~ sequence + subject%in%sequence + period + treatment,`

data = yourdata)

res1 <- rstandard(mod) # 1. Internally studentized (standardized)

res2 <- rstudent(mod) # 2. Externally studentized

*i.e.*, it might be that you detect more outliers.BTW,

*which*outlier test are you thinking of? See also there and this thread at stackoverflow.—

Helmut Schütz

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

Science Quotes

*Dif-tor heh smusma*🖖🏼 Довге життя Україна!_{}Helmut Schütz

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

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### Complete thread:

- Outlier Test using R-Software and Phoenix WinNonlin software in the BE udayk 2020-03-06 09:00
- Outlier Test using R-Software and Phoenix WinNonlin software in the BE ping4santosh 2020-03-11 14:58
- Studentized & standardized residualsHelmut 2020-03-13 11:21
- Outlier Test using R-Software: Lund test ping4santosh 2020-03-14 14:52
- Outlier Test using R-Software: Lund test udayk 2020-03-20 07:05
- Outlier Test using R-Software: Lund test ping4santosh 2020-03-20 10:07

- Outlier Test using R-Software: Lund test udayk 2020-03-20 07:05
- bear for outlier detection analysis? yjlee168 2020-03-20 14:45