Five people are on a diet-reducing plan. Estimate the regression for the relationship between the number of pounds of weight loss and the number of weeks each of the five people was on the plan. Accumulated data consists of five paired observations: the first element of each pair indicates the number of weeks the person was on the diet and the second element indicates the number of pounds the person lost. These five paired observations are given, where X represents the number of weeks on the diet and Y represents the number of pounds lost.

Quantitative Relationship between Two Variables
X	Y
3	6
2	5
1	4
4	9
5	11

The first pair of observations (X = 3, Y = 6) indicates that the first person lost 6 pounds in 3 weeks; the second pair (X = 2, Y = 5) indicates the second person lost 5 pounds in 2 weeks. In like manner, the third pair (X = 1, Y = 4) indicates that the third person lost 4 pounds in 1 week; the fourth pair (X = 4, Y = 9) indicates that the person lost 9 pounds in 4 weeks; and the fifth pair (X = 5, Y = 11) indicates the fifth person lost 11 pounds in 5 weeks. Find the least squares regression line relating weight loss to weeks on the diet. How many weeks should one diet expect to lose 20 pounds? How much variation in weight loss is explained by dieting?