15.8. Modeling with Regression http://www.ck12.org
a. Use the calculator to find the maximum of the parabola. Thexcoordinate represents the “perfect” amount of
sleep.
b. You can substitutex=5 into the equation, or you can let the function you created and stored iny 1 simply act on
the 5.
c. The relevant domain is between about 2 hours and 10 hours of sleep. Beyond those numbers of sleep, the model
will probably not make a whole lot of sense. How could someone get negative hours of sleep?
d. You can substitute ˆy=1500 into the equation and solve forxusing the quadratic formula, or you can graph the
liney=1500 and use the calculator to produce the two intersecting points.