R.
My daughter started the same thing at about that age. She only hit and bite me and the sitter. She only did when she wanted attention or she was frustrated. She still bites me from time to time. It is only when she is so upset about something she doesn't know what to do. We put her in time out when she does and tell her very loudly and strenly "OUCH That hurt" she gets upset that she hurt me and she doesn't do it for about 3-4 weeks then she forgets and will do it again. Each time it seems to last longer. She is now 2 and it is a slow process but working.