A ratio shows the proportional relationship of one number to another. They are used for various purposes, including financial and statistical analysis. A ratio can be expressed as a fraction with one number in the numerator (above the line) and the other in the denominator (below the line), as an expression of the type "2:1" or as a statement like "2 to 1." A population ratio shows the relationship of one population subgroup to another or a subgroup to the entire population.

Determine the size of the first population group. For example, assume there are 10,000 Asians in the total population.

Determine the size of the second population group. For example, assume there are 20,000 Hispanics in the total population.

Divide the Hispanic population, 20,000, by the Asian population, 10,000, to find the ratio of Hispanics to Asians: 20,000 divided by 10,000 is 2 to 1 -- there are two Hispanics to every Asian.