https://www.gregmat.com/quizzes/quiz/im-overwhelmed-data-analysis-progress-quiz-7 (Question 8)
I have a query related to empty set. Should we exclude it from both even and odd elements, or no? How is it treated? I initially thought empty set=zero, and hence is even.
Kindly refer to (I'm Overwhelmed) Data Analysis Progress Quiz #7 Question #8
You’re thinking about the “number of elements” in a given subset, but the question is asking you for subsets which contain only elements that are even.
Nonetheless, the empty set should still count (for a different reason than you and the other thread mentioned), and thus the correct answer must be 8 (not 7). “Every element in the empty set is even” is a true statement (it’s vacuously true) because there are no elements in the empty set that are odd. A good safeguard for this question would be to ask for subsets of at least size 1.