Please fill the blank based on the following information. An algorithm S of complexity O(n) is used to solve a problem. You execute the algorithm many times and collect timing information(see table). You are puzzled by the time you observe. State what you observe and give a reasonable explanation.

Data size: 50 100 250 500 750 1000 1500 10000 20000 50000

Time: 2 8 51 205 456 811 1203 8100 16200 40500

The performance is _____________ in the second half of the time chart but___________ in the first half. Beta is about ______________. ________________that point,_________________ performance would not be expected to be a reliable indicator or estimate of performance. In this case it ______________a reliable indicator.