With p = 0.600 and q = 0.400, about 48.0% of this population are carriers.
Carriers (Aa) make up 48.0% of the population, more than double the 16.0% who express the recessive phenotype when q is 0.400.
The three genotype frequencies p², 2pq, and q² always sum to exactly 100%; they are the expanded terms of (p + q)².
Carrier frequency (2pq) peaks at 50% when p = q = 0.5 and falls off as either allele dominates.
This baseline assumes random mating, no selection or mutation, no migration, and a large population. Any real deviation signals one of these forces at work.
Next stepSwitch to "Observed genotype counts" mode and enable the chi-square test to check if your population is in equilibrium.