[thekoma]

Out of context, the expression "the uncertainty in the number of trials" would refer to missing knowledge in terms of how many trials actually ran.

In the context of the post this doesn't make sense, so the reader is left to hypothesize what the writer actually meant.

[usgroup]

I agree it could be clearer but as a general rule, if you find an interpretation under which the question doesn’t make sense, try considering another interpretation.