Hero (Skillet song) Hero (Skillet song) "Hero" is the first single of the 2009 album "Awake" by the American Christian rock band Skillet and is the first track on the album. The song talks about mankind's need for a hero with the hero being Jesus Christ. It is the fourth single by Skillet to be released to physical media. The single sold 12,000 copies in its first week. It was used in a promo on NBC for the 2009 NFL Kickoff game between the Pittsburgh Steelers and the Tennessee Titans, as well as the Week 17 Sunday Night Football game between the Cincinnati
Differential item functioning Differential item functioning Differential item functioning (DIF) is a statistical characteristic of an item that shows the extent to which the item might be measuring different abilities for members of separate subgroups. Average item scores for subgroups having the same overall score on the test are compared to determine whether the item is measuring in essentially the same way for all subgroups. The presence of DIF requires review and judgment, and it does not necessarily indicate the presence of bias. DIF analysis provides an indication of unexpected behavior of items on a test. An item does not display DIF if