Which factor do biologists calculate when they determine whether a population is in hardy-weinberg equilibrium? a. mutation rate, b. genotype frequencies, c. number of phenotypes, d. rate of migration

The correct answer would be b. genotype frequencies.

Hardy-Weinberg law states that the genotype frequencies of a population remain the same over several generations in the absence of disturbing phenomenon such as natural selection, genetic drift, migration, et cetera.

The genotype frequencies satisfy the Hardy-Weinberg equation  

q² + p² + 2 pq = 1, and  

q + p = 1

p² and q²refer to frequencies of homozygous dominant and homozygous recessive trait respectively.

2 pq refers to the frequency of heterozygous dominant trait.

p and q refer to the frequencies of the dominant and recessive allele.