For example, a lower volatility stock may have an expected (average) return of 7%, with annual volatility of 5%. This would indicate returns from approximately negative 3% to positive 17% most of the time (19 times out of 20, or 95% via a two standard deviation rule).
To join the enlisted ranks, in general you must: 1  Be a U.S. citizen or Green Card holder Non-citizens must speak, read, and write English fluently. Non-citizens must currently live in the U.S. 2  Be in good health. 3  Be 17 to 40 years old (different branches have different age requirements). View a chart of age requirements by service.
The earliest age at which individuals can enlist in any branch of the U.S. military is age 17, but at this age, they must have parental consent. However, the average age is higher given that some people enlist later. The maximum age for most branches is 35. On its recruiting website, the U.S. Army reported an average enlistment age of just under 21 in 2012. This was slightly lower than the average age from 2010 and 2011.