Average Rate Formula
Average, Median, and Mode
Permutations and Combinations
The number of permutations of n distinct objects is n! = n(n – 1)(n – 2)···(3)(2)(1)
The number of permutations of n objects, a of which are indistinguishable, and b of which
are indistinguishable, etc., is
The number of permutations of n objects, taken r at a time, is
Median = middle value (or average of two middle values)
Mode = most frequent value
Sum of the terms = (Average) × (Number of terms)