Set #1 = {1, 3, 5, 7}
has a standard deviation of A, and
Set #2 = {4, 4, 4, 4}
has a standard deviation of B.
How do A & B compare?
A > B = 0
A set with all the same elements has no deviation from the mean, so B = 0. The elements in A are different from one another, so there's some deviation, which means A > 0. Therefore, A > B.