Answer: Both B and C.
- A Variance
- B Second raw moment
- C Mean square
- D Both B and C
Correct answer: D. Both B and C
Explanation: E[Xᵏ] = k-th raw moment (moment about zero/origin). So E[X²] = second raw moment. It is also called mean square (average of squared values). Note: Var(X) = E[X²] − (E[X])² ≠ E[X²] unless E[X]=0. Answer: both B (second raw moment) and C (mean square).
Venn diagram of the universal set U with events A and B, showing the intersection (A and B), the parts unique to each event, and the complement region outside both.
Concept context
Chance, events, conditional probability, and Bayes theorem