What is the primary difference between this demonstration and our chapter examples, keeping the chapter "Time Value of Money I" in mind?

Explain the significance of Dr. van Biezen’s comment at 4:32 regarding a difference when payments are made at the beginning of each pay period rather than the end.

What is the primary difference between a fixed annuity and a variable annuity?

Annuities are often recommended to retirees and seniors. Why would a fixed annuity be more attractive to such a person than a variable annuity?