A researcher wants to explore the relationship between the following two variables, Weight 1 and Weight 2.

Weight 1 Weight 2
130 138
160 156
220 224
125 119
205 213

 

Suppose that Weight 1 is the weight (in pounds) of a sample of five individuals before beginning a weight-loss diet, and Weight 2 is the weight in (pounds) of the same five individuals after the diet. If we would like to test the effectiveness of the diet, which of the following is the appropriate inference method?