< the specifications say this is a 16.2 mega pixel camera > So far, so good!
<< when I take a picture in the RAW format with the camera the mega pixel size of the file is right around 23 or 24 >>
There it is! Ok, let's see
"16.2 mega pixel" is clear, it is the resolution.
When the camera takes a shot, it will record the info of you picture on the memory media you put in your body. Your camera will not save a picture on the card but will write data. This amount of data for each file represents all the info relative to the picture you just took plus the metadata you have chosen to be included.
On this card, as well as on your computer, data files are measured in megabytes, MB.
Megabytes MB, megapixels MP… huh? now you got it!
Your camera has a sensor of 16,2 MP and record files that are 23-24 MB in the case of your RAW files. Da,Da!