"On an array of n=2^k numbers, where k is a nonnegative integer, the k order statistics 1,2,4,8,... 2^(k-1) can all be determined in a total of O(n) time in the worst case"

Is this statement true or false?? Please state your reasoning.
I have no idea how to start to solve that problem even though I know this statement is true. Anyone can help me???