DPI = Dots per Inch and is used in printing. When talking about resolution of a picture PPI is used Pixels per Inch.
Raw files do not have a PPI, it is just raw data (pixels) The program you use to convert from Raw to another format (TIF, JPG etc) you should be able to set it up for bit depth, PPI etc.
In Adobe Camera Raw click on the blue line at the bottom to adjust the settings you require...
Do I resize the photos to 300 dpi in Image Size? Will that work? Does it matter? Can we get great 8x10s with 72 dpi as long as the pixel size is appropriate? Help!
In addition to the other answers, maybe for a better understanding for ppi you open a photo in Photoshop and choose from the menu Image / Image size.
Inhere you have pixel dimensions and the total amount of file size and pixel width and height.
At the bottom you have the option to resample the image. Be sure to have set this to off.
Now change the resolution to whatever you want and you will see that the width and height changes for the document but the pixel amount and file size stays the same.
As Curt stated, a screen shows 72 pixels per inch but for a print you need more. Whether you change the document size or the resolution, as long as you don't resample the file the amount of pixels stays the same and you be able to see it on screen as well as use for a print.
So the pixel amount and file size is important for the quality, the ppi setting can be variated without problems for the same file size. A screen usually auto adjust the size and in print dialog you can set the option to fit the page or other customized settings.
Nevertheless the whole world seems to be wanting the magic number of 300 dpi. And to please them just follow the link Paul provided for the ACR window and set your files to 300 ppi.
And as long as your not professional involved in publishing and printing you don't have to bother about calling it ppi or dpi, the vast majority does not know the difference either
Thanks, I was able to get a better understanding from all three answers I received, all very helpful...thanks guys! I found that RAW files are, on average, 12 mg each, some are up to 25 mg after photoshopping them...I didn't really want to give my client 25 pictures that size, so I wanted to reduce them and panicked when I found the 72 dpi might not be sufficient to print a portrait...I get it now...you guys are great to take time to help me. Thanks.