Just a couple of points that seem to need making repeatedly.
First, if you don't statistically analyze your data both to prove a difference (if present) is significant or not AND to prove a lack of difference is significant, you aren't really "proving" anything with your data (i.e. study) - further remember that in studies of this sort "proving" usually means 95% certainty, not 99 or 100%. That's probably good enough, but still...
Second, a 320k MP3 is closer (in actual data flow rates) to CD than CD is to SACD or 24/192 LPCM.
First, if you don't statistically analyze your data both to prove a difference (if present) is significant or not AND to prove a lack of difference is significant, you aren't really "proving" anything with your data (i.e. study) - further remember that in studies of this sort "proving" usually means 95% certainty, not 99 or 100%. That's probably good enough, but still...
Second, a 320k MP3 is closer (in actual data flow rates) to CD than CD is to SACD or 24/192 LPCM.