Whereas recruits who join as officers tend to be upwardly-mobile,[14][15] most enlisted personnel have a childhood background of relative socio-economic deprivation.[16][17][18] For example, after the US suspended conscription in 1973, "the military disproportionately attracted African American men, men from lower-status socioeconomic backgrounds, men who had been in nonacademic high school programs, and men whose high school grades tended to be low".[14]
The ASVAB also known as the Armed Services Vocational Aptitude Battery is a test that measures your aptitude which is how well you do something.  A common mistake by most people is thinking that it is a measure of you IQ. Many people either forget this or don’t know this and they get worked up about the exam.  Saying that, it is also important to take a ASVAB sample test to insure you know what type of questions will be asked.    Another thing to keep in mind is every person in the armed forces has to take the exam and you are not being called out to take it. 

Militaries often function as societies within societies, by having their own military communities, economies, education, medicine, and other aspects of a functioning civilian society. Although a 'military' is not limited to nations in of itself as many private military companies (or PMC's) can be used or 'hired' by organisations and figures as security, escort, or other means of protection; where police, agencies, or militaries are absent or not trusted.

Military tactics concerns itself with the methods for engaging and defeating the enemy in direct combat. Military tactics are usually used by units over hours or days, and are focused on the specific, close proximity tasks and objectives of squadrons, companies, battalions, regiments, brigades, and divisions, and their naval and air force equivalents.[31]
Battlefield commission: under certain conditions, enlisted personnel who have skills that separate them from their peers can become officers by direct commissioning of a commander so authorized to grant them. This type of commission is rarely granted and is reserved only for the most exceptional enlisted personnel; it is done on an ad hoc basis, typically only in wartime. No direct battlefield commissions have been awarded since the Vietnam War. The Navy and Air Force do not employ this commissioning path.
These relationships are seen from the perspective of political-military relations, the military-industrial complex mentioned above, and the socio-military relationship. The last can be divided between those segments of society that offer support for the military, those who voice opposition to the military, the voluntary and involuntary civilians in the military forces, the populations of civilians in a combat zone, and of course the military's self-perception.
After the final ability estimate is computed, it is converted to a standard score on the ASVAB score scale that has been statistically linked to the ability estimate through a process called equating. Equating studies are conducted for every paper and pencil ASVAB form to ensure that scores have the same meaning regardless of which test form the examinee receives.