Given two byte arrays of data captured from a microphone, how can I determine which one has more spikes in noise? I would assume there is an algorithm I can apply to the data, but I have no idea where to start.

Getting down to it, I need to be able to determine when a baby is crying vs ambient noise in the room.

If it helps, I am using the Microsoft.Xna.Framework.Audio.Microphone class to capture the sound.