The bonus disc alone makes this worth most of the price. The Hollywood High live songs (9 of them) are amazingly well recorded, very energetic great performance, with an enthusiastic crowd that doesn't intrude on the music. If you remember the live "El Mocambo" bonus disc that was part of an EC boxed set several years ago, well this is FAR better than that. The Hollywood High set alone could have been released as a great live CD, possibly the only reason it wasn't was because it would be seen as too short. The "bonus disc" here has other songs (B sides, etc.) not from the original "Armed Forces" which are worthy and interesting as well.
The IRT model underlying ASVAB scoring is the three-parameter logistic (3PL) model. The 3PL model represents the probability that an examinee at a given level of ability will respond correctly to an individual item with given characteristics. Specifically, the item characteristics represented in the 3PL model are difficulty, discrimination (i.e., how well the item discriminates among examinees of differing levels of ability), and guessing (i.e., the likelihood that a very low ability examinee would respond correctly simply by guessing).