Backtranform lsmeans in R: 在R中反转换lsmeans:

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英文:

Backtranform lsmeans in R

问题

我已在R中创建了一个简单的线性回归模型,其中我对响应进行了对数变换。自变量是分类变量,具有80个级别。然后我使用emmeans进行成对测试。如何将emmeans反变换为与响应相同的刻度(而不是对数刻度)?我在R中使用emmeans包。

英文:

I have created a simple linear regression model in R where I have log transformed the response. The independent variable is categorical with 80 levels. Then I use emmeans for pairwise tests. How can I backtransform the emmeans to have the same scale as the response (not the log scale)? I use the emmeans package in R.

答案1

得分: 3

我认为这只是

summary(emmeans(...), type = "response")

吗?关于转换和链接函数的说明可以在这里找到:转换和链接函数的文档

例如:

library(emmeans)
m1 <- lm(log(mpg) ~ factor(cyl), mtcars)
summary(emmeans(m1, ~cyl), type = "response")
 cyl response    SE df lower.CL upper.CL
   4     26.3 1.268 29     23.9     29.0
   6     19.7 1.190 29     17.4     22.3
   8     14.9 0.636 29     13.6     16.2
使用的置信水平:0.95
区间从对数尺度反变换

请注意,如果您使用pairs(emmeans(m1, ~cyl), type = "response"),它将为您提供成对的比率,但请注意测试是在对数尺度上执行的(正如应该的那样)。

英文:

I think this is just

summary(emmeans(...), type = &quot;response&quot;)

? There is a vignette on transformations and link functions

e.g.

library(emmeans)
m1 &lt;- lm(log(mpg) ~ factor(cyl), mtcars)
summary(emmeans(m1, ~cyl), type = &quot;response&quot;)
 cyl response    SE df lower.CL upper.CL
   4     26.3 1.268 29     23.9     29.0
   6     19.7 1.190 29     17.4     22.3
   8     14.9 0.636 29     13.6     16.2
Confidence level used: 0.95 
Intervals are back-transformed from the log scale 

Note that if you use pairs(emmeans(m1, ~cyl), type = &quot;response&quot;) it will give you the pairwise ratios, but notes that the tests are performed on the log scale (as they should be)

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  • 本文由 发表于 2023年5月24日 20:14:39
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