从lmer模型中提取贝叶斯p值
我试图从我建立的从lmer模型中提取贝叶斯p值,r,bayesian,lme4,p-value,R,Bayesian,Lme4,P Value,我试图从我建立的lmer模型中提取贝叶斯p值(即,如果点估计为负,则估计值的比例>0;如果点估计为正,则估计值的比例
lmer
模型中提取贝叶斯p值(即,如果点估计为负,则估计值的比例>0;如果点估计为正,则估计值的比例<0))。我理解“p值”本质上是频繁出现的,但我需要贝叶斯p值来安抚评论者()
为了再现性的目的,我使用R的数据集来说明我的问题。数据集:
library(datasets)
data(ChickWeight) #importing data from base R
summary(ChickWeight)
weight Time Chick Diet
Min. : 35.0 Min. : 0.00 13 : 12 1:220
1st Qu.: 63.0 1st Qu.: 4.00 9 : 12 2:120
Median :103.0 Median :10.00 20 : 12 3:120
Mean :121.8 Mean :10.72 10 : 12 4:118
3rd Qu.:163.8 3rd Qu.:16.00 17 : 12
Max. :373.0 Max. :21.00 19 : 12
(Other):506
我的真实数据既有连续的预测变量,也有离散的预测变量,而且对个体身份有随机影响
创建lmer
模型:
install.packages("lme4", dependencies=TRUE)
library(lme4)
m1<-lmer(weight ~ Time + Diet+ (1|Chick), data=ChickWeight)
summary(m1)
Linear mixed model fit by REML ['lmerMod']
Formula: weight ~ Time + Diet + (1 | Chick)
Data: ChickWeight
REML criterion at convergence: 5584
Scaled residuals:
Min 1Q Median 3Q Max
-3.0591 -0.5779 -0.1182 0.4962 3.4515
Random effects:
Groups Name Variance Std.Dev.
Chick (Intercept) 525.4 22.92
Residual 799.4 28.27
Number of obs: 578, groups: Chick, 50
Fixed effects:
Estimate Std. Error t value
(Intercept) 11.2438 5.7887 1.942
Time 8.7172 0.1755 49.684
Diet2 16.2100 9.4643 1.713
Diet3 36.5433 9.4643 3.861
Diet4 30.0129 9.4708 3.169
Correlation of Fixed Effects:
(Intr) Time Diet2 Diet3
Time -0.307
Diet2 -0.550 -0.015
Diet3 -0.550 -0.015 0.339
Diet4 -0.550 -0.011 0.339 0.339
现在我想得到贝叶斯p值:
install.packages("conting", dependencies=TRUE)
library(conting)
bayespval(object=sm1, n.burnin = 0, thin = 1, statistic = "X2")
#this last line is the line I am having trouble with
Error: $ operator not defined for this S4 class
关于我如何设置模型m1
,提取每个估算值的贝叶斯p值的正确格式是什么?
有一个发布的示例,但我的模型并不像他们的模型那个样设置
我不需要使用这个软件包,我很乐意从1000个模拟中计算出来。在这种情况下,我需要知道如何计算有多少估算值低于/高于零。该数字/1000(估计总数)将是贝叶斯p值。提取贝叶斯p值(即,如果点估计为负,则大于0的估计比例;如果点估计为正,则小于0的估计比例)可以提取每个模拟的点估计值,然后除以模拟数 要使用
ChickWeight
数据集和上述模型执行此操作,您需要:
library(datasets)
data(ChickWeight)
m1<-lmer(weight ~ Time + Diet+ (1|Chick), data=ChickWeight)
sm1<-sim(m1,1000)
smfixef=sm1@fixef
smfixef=as.mcmc(smfixef) #this has the 1000 simulations in it for the fixed effects
as.mcmc(smfixef)
Markov Chain Monte Carlo (MCMC) output:
Start = 1
End = 1000
Thinning interval = 1
(Intercept) Time Diet2 Diet3 Diet4
[1,] 17.52609243 8.381517 7.47169881 46.442343 19.7164997 #simulation 1
[2,] 16.52854430 8.859378 8.83279931 29.017547 25.4610474 #simulation 2
[3,] 4.00702870 8.830302 29.68309621 47.459395 35.1939344 #simulation 3
[4,] 16.44162722 8.599929 15.87393285 31.946265 33.7513144 #simulation 4
[5,] 21.07173579 8.596701 1.81909415 28.934133 19.0499998 #simulation 5
etc.
由于时间
变量的点估计值为正,因此您需要计算该变量的估计值低于零的次数:
p_Time=if_else(smfixef[,2]>0, 1,0) #Time variable (i.e., 2nd column)
sum_p_Time=sum(p_Time<1)
> sum_p_Time
0
sum\u p\u Time=sum(p\u Time sum\u p\u Time
0
在这种情况下,它表示所有估计值都在零以上,因此贝叶斯p值<0.001。这支持了我们在仅查看点估计值和95%可信区间时所看到的情况(即,时间
估计值为8.80,95%可信区间为(8.38,9.06).在这两种情况下,我们都看到人们强烈支持时间对体重产生影响
sum_p_Time=sum(p_Time<1)
> sum_p_Time
0