Let x be the age of a licensed driver in years. Let y be the percentage of all fatal accidents (for a given age) due to failure to yield the right-of-way. For example, the first data pair states that 5% of all fatal accidents involving 37-year-olds are due to failure to yield the right-of-way. The Wall Street Journal article referenced in Problem 11 reported the following data:
Complete parts (a) through (e), given ˆ‘x = 372, ˆ‘y = 112, ˆ‘x2 = 24,814, ˆ‘y2 = 3194, ˆ‘xy = 8254, and r ‰ˆ 0.943.
(a) Draw a scatter diagram displaying the data.
(b) Verify the given sums ˆ‘x, ˆ‘y, ˆ‘x2, ˆ‘y2, and ˆ‘xy and the value of the sample correlation coefficient r.
(c) Find x, y, a, and b. Then find the equation of the least-squares line ŷ = α + bx.

(e) Find the value of the coefficient of determination r2. What percentage of the variation in y can be explained by the corresponding variation in x and the least-squares line? What percentage is unexplained?
(f) Predict the percentage of all fatal accidents due to failing to yield the right-of-way for 70-year-olds.