Do we need a few definitions here?
"Audio CDs
Audio CDs do not use WAV as their sound format, instead using Red Book audio. The commonality is that both audio CDs and WAV files have the audio data encoded in PCM. WAV is a data file format for computer use. If one were to transfer an audio CD bit stream to WAV files and record them onto a CD-R as a data disc (in ISO format), the CD could not be played in a player that was only designed to play audio CDs."
http://en.wikipedia.org/wiki/WAV
"Bit rate
The bit rate is variable for MP3 files. The general rule is that more information is included from the original sound file when a higher bit rate is used, and thus the higher the quality during playback. In the early days of MP3 encoding, a fixed bit rate was used for the entire file.
Bit rates available in MPEG-1 Layer 3 are 32, 40, 48, 56, 64, 80, 96, 112, 128, 160, 192, 224, 256 and 320 kbit/s, and the available sample frequencies are 32, 44.1 and 48 kHz. 44.1 kHz is almost always used (coincides with the sampling rate of compact discs), and 128 kbit/s has become the de facto "good enough" standard, although 192 kbit/s is becoming increasingly popular over peer-to-peer file sharing networks. MPEG-2 and [the non-official] MPEG-2.5 includes some additional bit rates: 8, 16, 24, 32, 40, 48, 56, 64, 80, 96, 112, 128, 144, 160 kbit/s.
Variable bit rates (VBR) are also possible. Audio in MP3 files is divided into frames (which have their own bit rate), so it is possible to change the bit rate dynamically as the file is encoded (although not originally implemented, VBR is in extensive use today). This technique makes it possible to use more bits for parts of the sound with higher dynamics (more sound movement) and fewer bits for parts with lower dynamics, further increasing quality and decreasing storage space. This method compares to a sound activated tape recorder that reduces tape consumption by not recording silence. Some encoders utilize this technique to a great extent.
Non-standard bitrates up to 640 kbit/s can be achieved with the LAME encoder and the --freeformat option, however few MP3 players can play those files."
http://en.wikipedia.org/wiki/MP3#Bit_rate