Question

The number of people attending graduate school at a university may be

modeled by the quadratic regression equation y = 6x2 - 30% +6, where x
represents the year. Based on the regression equation, which year is the best
prediction for when 906 people will attend graduate school?
O
O
A. Year 11
B. Year 15
C. Year 6
D. Year 9
O

Answer 1

B. Year 15

Explanation:

Along with helping you do quadratic regression, a graphing calculator can help you evaluate quadratic functions. This one has a value of 906 when x=15.

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By hand, you would set y=906 and solve for x:

906 = 6x^2 -30x +6

151 = x^2 -5x +1

156.25 = x^2 -5x +6.25 . . . . . . add 5.25 to complete the square

12.5^2 = (x -2.5)^2 . . . . . . . . . . write as squares if you like

12.5 = x -2.5 . . . . . . take the positive square root

15 = x . . . . . add 2.5

Year 15 is the year 906 people are predicted to attend graduate school.