Not this shit again.
Yes, it is.
https://en.wikipedia.org/wiki/Binomial_distribution
Though I'm not sure where 52% comes from. Unless I'm missing something, the formula for one 5* in 11 rolls is 11 * .06 * (.94)^10 = ~0.3555 or 35.55%.
6* is about right though. It's 11 * .005 * (.995)^10 = ~0.0523 or 5.23%.
Edit: Oh, we're using different formulas. My formula is the %age of getting EXACTLY one 5* or 6*. The other formula is getting AT LEAST one 5* or 6*.