谁能解释mirt包中的Mixedmirt函数的输出？

Question

我想在项目响应模型（例如：2PL模型）中包括人-项目协变量，但是我对如何解释输出感到困惑 （如图所示）。像如何理解groupG1和a1（或d）的系数之间的关系？ 下面是我的代码：

#make some data
set.seed(1234)
N <- 750
a <- matrix(rlnorm(10,.3,1),10,1)
d <- matrix(rnorm(10), 10)
Theta <- matrix(sort(rnorm(N)))
pseudoIQ <- Theta * 5 + 100  + rnorm(N, 0 , 5)
pseudoIQ <- (pseudoIQ - mean(pseudoIQ))/10  #rescale variable for numerical stability
group <- factor(rep(c('G1','G2','G3'), each = N/3))
data <- simdata(a,d,N, itemtype = rep('2PL',10), Theta=Theta)
covdata <- data.frame(group, pseudoIQ)
#specify IRT model
model <- 'Theta = 1-10'
# 2PL model
mod2 <- mixedmirt(data, covdata, model, fixed = ~ 0 + group + items + pseudoIQ,itemtype = '2PL')

coef(mod2)