Suppose we assume that the synonymous and non synonymous rates are both equal to the same value . Estimate , and compare with the values

Suppose we assume that the synonymous and non synonymous rates are both equal to the same value λ. Estimate λ, and compare with the values of λs and λn found in Exercises 41 and 42.
Mutation rates differ depending on whether changing the nucleotide base changes the amino acid (non synonymous sites) or not (synonymous sites). A piece of DNA has 200 non synonymous sites with 12 mutations and 100 synonymous sites with 15 mutations. Our goal is to estimate the mutation rate.