Stats is one area of maths I can't do.
In the Nfer 11+, one statistical question we often get is the based on taking one from each set of... How many combinations are there.
eg, making sandwiches with 3 types of bread, 4 types of filling and 3 types of garnish. Haw many sandwich combinations are there. We know the answer is 3x4x3.
I wouldn't class this as "Stats" but that's somewhat irrelevant.
This kind of question is way beyond the average 11 year old, but easy to do.
In the question, they will mention a set of numbers. Multiply them together and that's the answer. (in your example there are 3 *4 * 3 = 36 combinations)
It's essentially a gift question, as you need not spend any time thinking.
[edit: yes, I think this is the only type of combinations question you get - you don't get coloured-balls-in-a-bag-without-replacement questions, as far as I know - I did those in the first year of A level maths, not when I was 11]