Create and print summary results of a stochastic frontier model object returned by semsfa() with regard to the "CONDITIONAL EXPECTATION ESTIMATE" of the first step and to the "VARIANCE COMPONENTS ESTIMATE" of the compound error.
Usage
## S3 method for class 'semsfa'
summary(object, ...)
Arguments
object
an semsfa object returned by semsfa()
...
further arguments to the summary method are currently ignored
Details
Please note that if bootstrap is carried out the t-statistic is not reliable for testing the statistical significance of σ and λ, because these parameters are censored and cannot follow a t-distribution.
We suggest to compare the BIC of the semiparametric estimated model with the base model.
Value
summary.semsfa returns a list of class summary.semsfa that is identical to an object returned by semsfa() with few modifications if bootstrap is carried out:
b.t
t-statistic given the bootstrapped standard errors for λ and σ (b.se)
b.pv
p-values of the t-statistic
Note
summary returns the same result if applied to an object created with semsfa or efficiencies.semsfa
Author(s)
Giancarlo Ferrara and Francesco Vidoli
See Also
semsfa, efficiencies.semsfa
Examples
#generate data
set.seed(0)
n<-200
x<- runif(n, 1, 2)
fy<- 2+30*x-5*x^2
v<- rnorm(n, 0, 1)
u<- abs(rnorm(n,0,2.5))
#production frontier
y <- fy + v - u
dati<-data.frame(y,x)
#first-step: gam, second-step: fan (default)
#without bootstrap
o<-semsfa(y~s(x),dati,sem.method="gam")
summary(o)
# ... with bootstrap
o<-semsfa(y~s(x),dati,sem.method="gam",n.boot=100)
summary(o)