The domain of the function is the set of all the values of x that would allow the function to have real values. Since the radicand is x - 3, the value of x cannot be less than 3 because that would make the value of sqrt (x - 3) an imaginary number. Thus, the domain should be all numbers GREATER than or equal to 3.
that is the definition of "mean". it cuts the possible outcomes weighed with their probabilities (actual occurrences vs. possible occurrences) in 2 halves.
