replaceRHSByVariable:
In BERENZ/RISQ: What the package does (short line)

1	replaceRHSByVariable(formula, variable)

`formula`
`variable`

##---- Should be DIRECTLY executable !! ----
##-- ==>  Define data, use random,
##--	or do  help(data=index)  for the standard data sets.

## The function is currently defined as
function (formula, variable) 
{
    replacement <- as.formula(paste(". ~ ", variable, sep = ""))
    formula <- update.formula(formula, replacement)
    return(formula)
  }