The marketing manager of a large supermarket chain would like to determine the effect of shelf space (in feet) on the weekly sales of international food (in hundreds of dollars). a random sample of 12 equal sized stores is selected, with the following results:
store shelf space(x) weekly sales(y)

1- 10 2.0
2- 10 2.6
3- 10 1.8
4- 15 2.3
5- 15 2.8
6- 15 3.0
7- 20 2.7
8- 20 3.1
9- 20 3.2
10- 25 3.0
11- 25 3.3
12- 25 3.5
using the equation of the regression line for these data, predict the average weekly sales (in hundreds of dollars) of international food for stores with 13 feet of shelf space for international food.