Imagine you are a cattle farmer and you are performing a dihybrid cross to determine if the alleles of gene a and gene b assort independently. you mate a bull with the aabb genotype with a cow that has the aabb genotype (a dominant over a; b dominant over b), cross the f1’s with themselves, and produce the following ratio of phenotypes in 160 offspring from the f2 generation:

character a trait/character b trait

89 dominant/dominant

28 dominant/recessive

32 recessive/dominant

11 recessive/recessive

remembering that mendel’s expected phenotype ratio is based on the assumption that the two genes’ alleles do assort independently, perform a chi square analysis to determine if these two genes assort independently. use 7.815 as your critical value of chi squared.