A clinical test on humans of a new drug is normally done in three phases.Phase I is conducted with a relatively small number of healthy volunteers.For example, Phase I of bexarotene involved only 14 subjects.Assume that we want to treat 14 healthy humans with this new drug, and we have 16 suitable volunteers available.

a) if the subjects are selected and treated in sequence, so that the trial is discontinued if anyone displays adverse effects, how many different sequential arrangements are possible if 14 people are selected from the 16 that are available?

For a), do I just do 16 C 14 on my calculator as order does not matter, they want as much possible arrangements right? IF so, it is a big number.

b) If 14 subjects are selected from the 16 that are available, and the 14 selected subject are treated at the same time, how many different treatment groups are possible.

Would this just be 14! ?

c) If 14 subjects are randomly selected and treated at the same time, what is the probability of selecting the 14 youngest subjects?

Wouldn't this be just P(14/16)?