The BLM reported that 16 jacks and 26 jennies had been captured through Day 10 of the Lake Pleasant roundup.
Do those results look like they came from a population that’s 50% males / 50% females?
The observed proportions are 38.1% male and 61.9% female.
The answer must be determined by calculation, using a basic statistical formula that accounts for random variation.
In this example p-bar = .5 and n = 42.
The calculated range of variation is .269 (26.9%) to .731 (73.1%), which includes the observed values, so there is no evidence that the population is not 50% males / 50% females.
The East Pershing roundup took 1,082 stallions and 1,245 mares off the range (as well as 365 foals).
Do those data look like they came from a herd that’s 50% males / 50% females?
The observed proportions are .465 and .535, and the calculated limits are .469 and .531, so there is some evidence of an abnormal sex ratio.
The problem often occurs in herds subject to the Montana Solution, which the advocates dismiss as mares living longer.
Western Horse Watchers Association 