15.10 The following data represent x=boat sales and y=boat trailer sales from 1995 through 2000.
year
boat sales
boat trailer sales
thousands
thousands
1995649
207
1996619
194
1997596
181
1998576
174
1999585
168
2000574
159
a) determine the least-squares regression line and interpret its slope
b) estimate, for a year during which 500,000 boats are sold, the number of boat trailers that would be sold.
c) what reasons might explain why the number of boat trailers sold per year is less then the number of boats sold per year?