probability help: what is the probability of that an individual will be between 16 and 21 years of age? - Help.com

1) you mean a person?

2) you mean “out of all the people on Earth today, how many are between 16 & 21?”

3) or, what the heck DO you mean?

Basic probability is the number of how many things you want over the number of how many things there are.

Say I flip a normal coin and I want the outcome to be heads. There is only 1 heads. There are two possible outcomes though, the other being 1 tails.

So the probability of me getting heads is 1 heads divided by 1 heads plus 1 tails, or 1/(1+1) = 1/2 = .5

To get percent probability, just multiply the result by ten. 0.5 x 10 = 50%

So to compute the probability of people ages 16 to 21 (I assume you mean that includes people ages 16 and 21 too?) You would take the total number of people that are 16 through 21 and divide that by the total world population.

Here is a site that collects census data about world populations. At this particular page, you can generate a table of population by age for specific countries and regions, including the world. (The world table will be at the bottom if you generate a report for the world.) The only bad thing is that it lists the populations of ages by age groups instead of each individual year. For instance, it’d list the population for age 15-19 in one group and age 20-24 in another.

http://geography.about.com/gi/dynamic…