Write, test and debug (if necessary) PHP scripts for the specifications that follow. Write functions and the code to test them.
Exercise 9.1
Parameter: An array of strings
Return Value: A list of unique string in the parameter array
Exercise 9.2
Parameter: An array of numbers
Return Value: The average and median of the number
Exercise 9.5
Parameter: A string of numbers separated by spaces
Return Value: The first four-digit number of the string; false if none.