Hello,
For this specific question, don’t we need to consider the case where all numbers in the original list are the same? (e.g., 3,3,3,3,3). In this case, shouldn’t the correct answer choice be inclusive of the original SD and mean?: a > or = b; c > or = d?
I may be wrong if the terminology for “set” automatically implies some different elements in the original set. Thanks so much!