RAID: dedicated and distributed parity
The answer to your question can be infered from the wWikipedia page on
"Standard RAID levels".

Parity is just one simple case of techniques for error detection, and the name
seems to be used here to stand for various techniques of error
detection and correction.

The idea of dedicated vs distributed parity, is related to whether the
redundancy of information is on a special dedicated disk or whether it
is distributed over all disks of the RAID system.

This does not apply to RAID 1 where redundancy is achieved by simple
duplication of Data.

In the case of RAID 3 (and apparently RAID 2), data is striped (read
"spread" for faster access) over several disk why the redundancy data
(parity bytes or bits) is in a separate dedicated disk.

In the case of RAID 5, the redundancy is spread over all the disks and mixed into the original base data
(distributed parity) so that the original data can be retrieved
from any set of n-1 disks, when any one of the n disks fails. The
content of the failed disk can be recomputed from the n-1 others.

Distributed parity seems to be preferred to dedicated parity, though the
wikipedia page is not really clear as to why. My own suspicion is that
it allows for more effective error correction than dedicated parity, which keeps the original data and the redundancy (parity) data separate.
But this should be checked.