25. Use the following passage to answer questions 25 and 26. Sarah is about to fly from New York to Los Angeles. She packs the night before and checks her list three times. Anxiety keeps her from sleeping well. The next morning, she accidentally puts salt in her coffee instead of sugar. She forgets her purse and has to go back to the house to get it. Finally, she arrives at the airport just in time to catch her flight. The flight is uneventful, and soon Sarah is landing at LAX. Her sister is waiting for her. What was the main idea of this passage?

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).

**Standard Scores are scores that have a fixed mean and standard deviation in the population of examinees. A Standard Score indicates how many units of the standard deviation a particular score is above or below the mean. In the case of the ASVAB subtests, the mean is set to 50 and the standard deviation is set to 10. Thus, a Standard Score of 40 indicates that the examinee scored 1 standard deviation below the mean. A Standard Score of 70 indicates that the examinee scored 2 standard deviations above the mean. To learn more about how standard scores are derived and used, click here.**

The ASVAB currently contains 9 sections (except the written test, which contains 8 sections). The duration of each test varies from as low as ten minutes up to 36 minutes for Arithmetic Reasoning; the entire ASVAB is three hours long. The test is typically administered in a computerized format at Military Entrance Processing Stations, known as MEPS, or at a satellite location called a Military Entrance Test (MET) site. The ASVAB is administered by computer at the MEPS, while a written version is given at most MET sites. Testing procedures vary depending on the mode of administration.[3]

*One ASVAB sub-measure, the Armed Forces Qualification Test (AFQT)--which is just a separate analysis of the same tests that focuses only on four of the subtests--is also population-referenced, but its score from 1-99 is a percentile score. This means that if you score a 73, you scored as well as or higher than 73% of test-takers in the national sample.*