The National Center for Education would like to estimate the average student debt for the class of 2010 for the state of Ohio with a 90% confidence interval and a margin of error within plus or minus $1,500. Assuming the standard deviation for student debt in this state is $9,000, the required sample size is .

The change in water level of a lake is modeled by a polynomial function, w(x). described how to find the x-intercepts of w(x) and how to construct a rough graph of w(x) so that the parks department can predict when there will be no chage in the water level. you may create a sample polynomial of degree 3 or higher to use in your explanations.