The following data, compiled by the superintendent of schools in a large metropolitan area, shows the average SAT verbal scores of high school seniors during the 5 years since the district implemented its "back-to-basics" program. Determine the equation of the least-squares line for these data. Use the result obtained to predict the average SAT verbal score of high school seniors 2 years from now (x = 7). Please round your answer to the nearest whole number.
A) y = - 2.9x + 450; 426
B) y = - 2.9x + 450; 416
C) y = - 2.8x + 440; 420
D) y = - 2.8x + 440; 422

Question

The following data, compiled by the superintendent of schools in a large metropolitan area, shows the average SAT verbal scores of high school seniors during the 5 years since the district implemented its "back-to-basics" program.  Determine the equation of the least-squares line for these data. Use the result obtained to predict the average SAT verbal score of high school seniors 2 years from now (x = 7). Please round your answer to the nearest whole number.
A) y = - 2.9x + 450; 426 
B) y = - 2.9x + 450; 416 
C) y = - 2.8x + 440; 420 
D) y = - 2.8x + 440; 422

Quizplus · Accepted Answer

Using a calculator or statistical software, we can obtain the equation of the least-squares line: ŷ = -2.8x + 440. To predict the average SAT verbal score of high school seniors 2 years from now, we can plug in x = 7:
ŷ = -2.8(7) + 440 = 420.4
Rounding to the nearest whole number gives us an answer of 420, which is given only by choice C. Therefore, the best choice is C.

The Following Data, Compiled by the Superintendent of Schools in a Large