背景:
我正在使用 R(特别是 R studio,版本 4.1.3)进行分层线性回归。我想在每个步骤中使用稳健的线性模型(使用 rlm
函数、MM 估计器),而不是传统的 OLS 模型(lm
函数)。这是因为我有一些有影响力的异常值。
- 例如,以下是我的“STEP 1”/“Model 1”代码示例:
注意:使用了 中的 f.robftest
函数sfsmisc
包从 beta 系数获取 p 值:
model1_controlsRLM = rlm(ER40_CR ~ Age_in_Yrs + Gender2, data = datasetfinal, method = c("MM"))
f.robftest(model2_EFcontrolsRML, var = "Age_in_Yrs")
f.robftest(model2_EFcontrolsRML, var = "Gender21")
- “STEP 2”/MODEL 2 代码示例:
model2_EFcontrolsRML = rlm(ER40_CR ~ Age_in_Yrs + Gender2 + CardSort_AgeAdj, data = datasetfinal, method = c("MM"))
f.robftest(model2_EFcontrolsRML, var = "Age_in_Yrs")
f.robftest(model2_EFcontrolsRML, var = "Gender21")
f.robftest(model2_EFcontrolsRML, var = "CardSort_AgeAdj)
- 然后使用 ANOVA 比较模型
anova(model1_controlsRLM, model2_EFcontrolsRML)'
[此处缺少 p 值,也没有确定如何比较 R^2 的变化或传达类似信息的等价度量]
我的问题
-
- 是否允许对分层线性回归中的每个步骤/模型使用 RLM(而不是标准 OLS)?
-
- 如果是这样,我如何计算调整后的 R^2 或适合 RLM 的等效指标的变化? [如果有影响的话,我愿意使用不同的估计器来代替 MM(例如,M 估计器)]。
-
- 如何获得比较两个 RLM 模型的 ANOVA 的 p 值(比较步骤 1 与步骤 2)
提前感谢您的帮助。
BACKGROUND:
I'm conducting a hierarchical linear regression using R (specifically R studio, Version 4.1.3). I want to use robust linear models (using the rlm
function, MM-estimator) for each of my step, instead of a traditional OLS model (lm
function). This is because I have some influential outliers.
- For example, here is an example of my "STEP 1"/"Model 1" code:
Note: used the f.robftest
function from the sfsmisc
package to get p-values from beta-coefficients:
model1_controlsRLM = rlm(ER40_CR ~ Age_in_Yrs + Gender2, data = datasetfinal, method = c("MM"))
f.robftest(model2_EFcontrolsRML, var = "Age_in_Yrs")
f.robftest(model2_EFcontrolsRML, var = "Gender21")
- Example of "STEP 2"/MODEL 2 code:
model2_EFcontrolsRML = rlm(ER40_CR ~ Age_in_Yrs + Gender2 + CardSort_AgeAdj, data = datasetfinal, method = c("MM"))
f.robftest(model2_EFcontrolsRML, var = "Age_in_Yrs")
f.robftest(model2_EFcontrolsRML, var = "Gender21")
f.robftest(model2_EFcontrolsRML, var = "CardSort_AgeAdj)
- And then comparing models using an ANOVA
anova(model1_controlsRLM, model2_EFcontrolsRML)'
[Missing p-values here, and also not sure how to compare changes in R^2 or an equivalence metric that would communicate similar information]
MY QUESTIONS
-
- Is it allowed to use an RLM (instead of standard OLS) for each step/model in a hierarchical linear regression?
-
- If so, how can I calculate changes in adjusted R^2 or an equivalent metric appropriate for RLMs? [I'm open to using a different estimator instead of MM (e.g., M-estimator) if this makes a difference].
-
- How do I get the p-values of my ANOVA comparing the two RLM models (comparing step 1 vs. step 2)
Thank you for your help in advance.
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