On a network, you might have 50 people trying to access, say, a seven-drive tower at the same time. The faster those drives locate and read the data, the faster the tower can process all 50 requests. The Random Access results indicate typical performance. Sequential access suggests the type of performance you will see reading large files, such as video. The last two tests measure performance when a drive slows itself down to read poorly recorded or damaged discs.
Higher numbers are better.