Compute Sargan's S
sargan(object, ..., lhs = object$lhs[1])
and object type '"felm"', the return value from felm
.
Not used at the moment.
in case of multiple left hand sides, specify the name of the left hand side for which you want to compute Sargan's S.
sargan
returns a numeric, the Sargan's S. The Basmann statistic is
returned in the '"basmann"' attribute.