Problem
In fruit flies, bristles are the hair-like structures that protrude from the body. Suppose in your laboratory population, the average number of bristles on 100 flies was 37.5. To investigate narrow sense heritability of the trait in this population, you interbred the 20% hairiest subpopulation which had an average of 40 bristles. The progeny of these hairy flies had an average of 38.7 bristles. What is the narrow sense heritability of this trait in your original population?