(v) Finding the median (The value of a numerical set that equally divides the number of values that are larger and smaller) of an array of sorted items
(v) Again i am not sure on this, maybe O(log n) since the array is sorted so you only need to search half the values, essentially a binary chop.
This one is O(1). You are interested in the item that is in the middle of the sorted array (for N odd), or the average of the two "closest" to the middle (for N even).
Since the data is ordered, you can simply examine the one or two elements needed for the result.