更新时间:2022-10-23 21:54:24
经过一些尝试和错误,使用 set.seed(123)
:
coefini = coef(glm(Outcome〜 group + Age,data = data.1,family = binomial(link =log))
fit2< -glm(Outcome〜Group + Age + BMI,data = data.1,family = binary =log),start = c(coefini,0))
摘要(fit2)
调用:
glm(formula = Outcome〜Group + Age + BMI,family = binomial(link =log),
data = data.1,start = c(coefini,0))
偏差余数:
最小1Q中位数3Q最高
-1.2457 -0.9699 -0.7725 1 .2737 1.6799
系数:
估计标准错误z值Pr(> | z |)
(截取)-1.5816964 1.0616813 -1.490 0.136
Group1 0.4987848 0.3958399 1.260 0.208
年龄0.0091428 0.0138985 0.658 0.511
BMI -0.0005498 0.0331120 -0.017 0.987
(二项式族的分散参数取为1)
空值:65.342在49***度
剩余偏差:63.456在46度的***
AIC:71.456
费舍尔计分迭代次数:3
I am conducting a log binomial regression in R. I want to control for covariates in the model (age and BMI- both continuous variables) whereas the dependent variable is Outcome(Yes or No) and independent variable is Group (1 or 2).
fit<-glm(Outcome~Group, data=data.1, family=binomial(link="log"))
and it works fine.
When I try putting age in the model, it still works fine. However, when I put BMI in the model, it gives me the following:
Error: no valid set of coefficients has been found: please supply starting values
I have been tried different combination of starting values such as:
fit<-glm(Outcome~Group+Age+BMI, data=data.1, family=binomial(link="log"), start=c(0,0,0,0)
or even start=(1,4) or start =4 but it still gives me the error.
It also says:
Error in glm.fit(x = c(1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, :
length of 'start' should equal 4 and correspond to initial coefs for c("(Intercept)", "group1", "age", "bmi")
.
Any help on this will be much appreciated!
Edited: adding reproducible example.
N=50
data.1=data.frame(Outcome=sample(c(0,0,1),N, rep=T),Age=runif(N,8,58),BMI=rnorm(N,25,6),
Group=rep(c(0,1),length.out=N))
data.1$Group<-as.factor(data.1$Group)
fit<-glm(Outcome~Group, data=data.1, family=binomial(link="log"))
coefini=coef(glm(Outcome~Group+Age+BMI, data=data.1,family =binomial(link = "logit") ))
fit<-glm(Outcome~Group+Age+BMI, data=data.1, family=binomial(link="log"),start=coefini)
After some trial and error, using set.seed(123)
:
coefini=coef(glm(Outcome~Group+Age, data=data.1,family =binomial(link = "log") ))
fit2<-glm(Outcome~Group+Age+BMI, data=data.1, family=binomial(link="log"),start=c(coefini,0))
summary(fit2)
Call:
glm(formula = Outcome ~ Group + Age + BMI, family = binomial(link = "log"),
data = data.1, start = c(coefini, 0))
Deviance Residuals:
Min 1Q Median 3Q Max
-1.2457 -0.9699 -0.7725 1.2737 1.6799
Coefficients:
Estimate Std. Error z value Pr(>|z|)
(Intercept) -1.5816964 1.0616813 -1.490 0.136
Group1 0.4987848 0.3958399 1.260 0.208
Age 0.0091428 0.0138985 0.658 0.511
BMI -0.0005498 0.0331120 -0.017 0.987
(Dispersion parameter for binomial family taken to be 1)
Null deviance: 65.342 on 49 degrees of freedom
Residual deviance: 63.456 on 46 degrees of freedom
AIC: 71.456
Number of Fisher Scoring iterations: 3