No - that is not at all common.

Something is certainly causing the instability so you might need to isolate the potential causes one at a time.


network issues (the most likely culprit but by far not the only one)
Apple TV needing a restore or perhaps just a reboot.
iOS device needing the same (restore or reboot).


Before restoring your iOS device, you might try the other steps first or also you could take your device to another network / Apple TV such as a retail store to test and make sure that's not the cause.

AirPlay on Apple TV 2 failing more often than it works
I have a simple application that needs the variance of a Polya Gamma distribution (I know the mean since I found it here- http://arxiv.org/abs/1205.0310). 

This paper says that there is a closed form solution for the variance, but I am not really a mathematician and cannot calculate it.

In short, does anyone know the closed form solution for the variance of the Polya Gamma distribution.

I would be very grateful.
