我用的是quantreg
R 中的包来计算分位数回归模型。在模型中,因变量(Y)为NAS_DELAY
,自变量(Xs)是SEANSON1TO4
, SEANSON2TO4
, SEANSON3TO4
.
模型是:
NAS_DELAY=aSEANSON1TO4+bSEANSON2TO4+cSEANSON3TO4+d
The SEANSON1TO4
,SEANSON2TO4
,SEANSON3TO4
是虚拟变量,0或1。我使用R计算截距和其他回归系数,但结果表明
“rq.fit.br(x,y,tau=tau,....)奇异设计矩阵中的错误;另外:警告消息 1:总结.rq(xi,....):278951 非正值菲”。
我不明白为什么。
"fit2<-summary(rq(NAS_DELAY ~SEASON1TO4+SEASON2TO4+SEASON3TO4,tau=c(0.1,0.2,0.3,0.4,0.5),data=fddata))
Error in base::backsolve(r, x, k = k, upper.tri = upper.tri, transpose = transpose, : singular matrix in 'backsolve'. First zero in diagonal [1]"
In addition: Warning messages:
1: In rq.fit.br(x, y, tau = tau, ...) : Solution may be nonunique
2: In rq.fit.br(x, y, tau = tau, ...) : Solution may be nonunique
3: In rq.fit.br(x, y, tau = tau, ...) : Solution may be nonunique
4: In rq.fit.br(x, y, tau = tau, ...) : Solution may be nonunique
5: In rq.fit.br(x, y, tau = tau, ...) : Solution may be nonunique
6: In summary.rq(xi, ...) : 188771 non-positive fis
我究竟做错了什么?