Let x be the age in years of a licensed automobile driver. Let y be the percentage of all fatal accidents (for a given age) due to speeding. For example, the first data pair indicates that 34% of all fatal accidents of 17yearolds are due to speeding.
Given: Σx = 329, Σy = 114, Σx^{2} = 18,263, Σy^{2} = 2582, Σxy = 3988, and r ≈ −0.961.
(c) Find x, and y. Then find the equation of the leastsquares line = a + bx. (Round your answers for x and y to two decimal places. Round your answers for a and b to three decimal places.)
x  =  
y  =  
=  + x  
(e) Find the value of the coefficient of determination
r^{2}. What percentage of the variation in
y can be explained by the corresponding variation
in x and the leastsquares line? What percentage is
unexplained? (Round your answer for r^{2}
to three decimal places. Round your answers for the percentages to
one decimal place.)


(f) Predict the percentage of all fatal accidents due to
speeding for 20yearolds. (Round your answer to two decimal
places.) 
(c)
b = SSxy / SSxx = 1370 / 2800 = 0.489
a = y  b x = 16.29  (0.489) * 47 = 39.273
y = 39.273  0.489 x
(e)
r2 = SSxy^2 / (SSxx * SSyy) = (1370)^2 / (2800 * 725.4286) = 0.924
explained % = 92.4 %
unexplained = 100  92.4 = 7.6 %
(f)
For x = 20,
y = 39.273  0.489 * 20 = 29.493
The percentage of all fatal accidents due to speeding for 20yearolds is 29.49
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