# A college bookstore must order books two months before each

A college bookstore must order books two months before   each semester starts. They believe that the number of books that will   ultimately be sold for any particular course is related to the number of   students registered for the course when the books are ordered. They would   like to develop a linear regression equation to help plan how many books to   order. From past records, the bookstore obtains the number of students   registered, X, and the number of books actually sold for a course, Y, for 12   different semesters. These data are below.          Semester      students          books    1                 36                 31     2                 28                 29     3                 35                 34     4                 39                 35     5                 30                 29     6                 30                 30     7                 31                 30     8                 38                 38     9                 36                 34     10              38                 33     11              29                 29     12              26                 26            a.   Graph the data      b.   Determine the correlation coefficient.    c.   Is there a strong relationship? If so determine the line of best fit.   d.   What is the equation of the regression line?   e.   Estimate the number of books to order if 33 students are in the current class