A couple of things. As has been pointed out, the thread title says it all about the criteria. Why would you only count core sports though? Athletic departments must follow the law (title IX), so that partially dictates what sports they will have. Also, athletic departments must make decisions about which sports they want and what they think will bring in the most money and be the most attractive to their fans. There are lots of decisions that go into this process and every athletic department must make them. So it only makes sense to compare entire athletic departments in this sense. Now if you just want to compare football and basketball, have it at, but really, all that indicates is how popular those two sports are; it doesn't give proper representation to the entire athletic department of the school (it can still be a good comparison though).
I love agriculture.
I believe NDSU is making a mistake by not pursing hockey. In past years, the Force have had higher average attendance then NDSU basketball (I believe the Force have more home games as well). The Force are in the USHL, one of the primary feeder leagues for UND and college hockey. The fact that they are out attending NDSU basketball says something for the popularity of hockey in the region that NDSU is located in.