Standard deviation for slot machine with free spin bonus

Hi everyone!

My name is Ignacio, I'm from Argentina and I'm currently developing a slot machine game for a class at university.

I've read many posts on the forum, and currently have a slot game that can calculate rtp, sd and vi theoretically or by simulation. So far so good.

I've added free spins bonus feature with scatter symbols and that's where the problem started. I can still calculate sd (and vi) by simulation, but am strugling to calculate them theoretically. I can correctly calculate rtp though.

I've read also on this forum that sd can only be simulated for complex situations and that sd (or vi) given in par sheets do not reflect reality (only 1 line, no bonus).

My questions are:
1) can I calculate sd theoretically having a free spin bonus?
2) sd in par sheets is only calculated for the base game?
3) sd in par sheets taking account bonus games is only calculated by simulation?
4) sd in par sheets for multiple lines is only calculated by simulation?

Thanks in advance for your time! It's a really great forum and I've learned a lot through it!

Regards, Ignacio

What you read I would agree with. Unless it is a simple one-line game, it would be much easier to calculate it by standard deviation. That is what I do.

@Wizard, thanks for the reply!

So no theoretical calculation. Just a big enough simulation, right?

And in case a PAR sheet is needed, should I calculate sd for base game/1 line only or use a simulated one?

Thanks again!