The following chart shows the population target (AML) for HMAs in Wyoming as a function of HMA size. Accordingly,
- Most of the HMAs contain 500,000 acres or less
- Most of the AMLs are 400 or less
- AMLs are loosely correlated with HMA size
The correlation coefficient for population and acreage is .46, which means the variations in HMA size are somewhat useful in explaining the variations in AMLs. The closer the value of this statistic to 1, the stronger the relationship between population and acreage.
If the correlation coefficient was 1, all of the data would fall on a straight line, indicating that population was proportional to acreage. HMAs of 200,000 acres would have twice as many horses as HMAs of 100,000 acres.
Note that the largest HMA does not have the largest AML and the smallest HMA does not have the smallest AML, but, in general, population goes up as acreage goes up.
Dispersion among the AMLs on the left side of the chart (smaller HMAs) is less than the dispersion among the AMLs on the right side of the chart (larger HMAs), a problem in statistical work known as ‘non-constant variance.’
RELATED: Wyoming HMA Stats.