Shikhar Mishra

#221 is doing some of this

@iuliadmtru can you update the data export from R to solve above issue.

See R comparison with SAS,Stata others. paper from 2010 - [paper](http://journal.r-project.org/archive/2009-2/RJournal_2009-2_Damico.pdf)

@ayushpatnaikgit Do we have to convert the multiple layers of `cluster` arguments into one "effective" `cluster`, if we are to use the single-stage approximation successfully? If so, need to add...

The reason is popsize is usually not 'known' it is estimated. In R, if the `fpc` parameter is not given, `popsize` in the survey objects remains `NULL`

We can look into the macro way? or perhaps later when more functionality related pending tasks done in main? Once more certainty on how many variables needed inside class, then...

@ayushpatnaikgit @iuliadmtru I think this does give correct total for any arbitrary design, should we look to complete and cleanup this for 0.2.0 release or look into later in December?

This should be integrated into `singledesign` branch with the new general survey design. Idea is to be similar to the single variance function in R, that can calculate the variance...

I am working on this right now

It is not feasible to complete this right now. Will look into it later