40 Quantitative models of music. Refer to the Chance (Fall 2004) study on modeling a certain pitch of a musical composition, presented in Exercise 20 . Recall that the number of times ( y ) a certain pitch occurs—called entropy—was modeled as a straight-line function of year of birth ( x ) of the composer. On the basis of the scatterplot of the data, the standard deviation s of the model is estimated to be s = .1. For a given year ( x ), about 95% of the actual entropy values ( y ) will fall within d units of their predicted values. Find the value of d .