estimate(test-ref) in bear [R for BE/BA]

posted by yjlee168 Homepage – Kaohsiung, Taiwan, 2018-12-12 18:58  – Posting: # 19686
Views: 2,309

Dear mittyri & all others,

» » As Yung-jin explained me that PE in R/bear is not a direct arithmetic difference, and it is estimated in a specific linear model in ANOVA.
» Sounds strange to me. Do we have the ratio of LSMeans, the ratio of GeoMeans and something else?:confused:
» Let's wait for Yung-jin's comments

Estimate(test-ref) in bear is not obtained directly from the difference of mean values or lsmean. It is obtained from one of coefficients of lm() function. I cut the outputs from a test run and show it as follows:   
---
 Summary Pivotal Parameters of BE Study 
------------------------------------------
 Dependent Variable: log(Cmax)           
------------------------------------------
        n1(R -> T) = 7
        n2(T -> R) = 7
          N(n1+n2) = 14
    Lower criteria = 80.000 %
    Upper criteria = 125.000 %
          MEAN-ref = 7.32951
         MEAN-test = 7.40146
               MSE = 0.01780339
                SE = 0.05043155
Estimate(test-ref) = 0.07195028

######  testing  ######
Call:
lm(formula = log(Cmax) ~ seq + subj:seq + prd + drug, data = TotalData,
    na.action = na.exclude)

Residuals:
     Min       1Q   Median       3Q      Max
-0.13876 -0.08473  0.00000  0.08473  0.13876

Coefficients: (14 not defined because of singularities)
            Estimate Std. Error t value Pr(>|t|)   
(Intercept)  7.48268    0.10086  74.187   <2e-16 ***
seq2        -0.06357    0.13343  -0.476   0.6423   
prd2        -0.05095    0.05043  -1.010   0.3323   
drug2        0.07195    0.05043   1.427   0.1792   
...
---

please browse "Interpreting regression coefficient in R" for more details (the explanations for the coefficient x32). Does anyone know the name of this coefficient in statistics? Thanks.

All the best,
---Yung-jin Lee
bear v2.8.4:- created by Hsin-ya Lee & Yung-jin Lee
Kaohsiung, Taiwan http://pkpd.kmu.edu.tw/bear
Download link (updated) -> here

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