1. Learning the mechanics. Suppose you ?t a least squares line to nine data points and calculate SSE = .219.

(a) Find s2, the estimator of the variance σ 2 of the random error term ε.

(b) Calculate s.

2. Learning the mechanics. Find SSE, s2, and s for the least squares lines in the following exercises. Interpret the value of s.

3. Quantitative models of music. Refer to the Chance (Fall 2004) study on modeling a certain pitch of a musical composition. 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. Based on the scatterplot of the data, the standard deviation σ 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.