I can't think of any book to recommend, other than maybe statistics textbooks for nonmathematicians.
There's are two things that come to mind: formulating questions precisely and concepts in simple statistics and hypothesis testing. Former I'd expect judges to be good at anyway (maybe modulo not having the expectation that things that should always be true should actually literally always be true). In later I'd expect the most important part to be understanding of distinctions between concepts that are tied together by base rates (e.g. conditional probabilities in different directions).