The copper content of 18-carat gold was measured by two methods for six different samples collected from a jewelry production plant. Sample Method 1 Method 2 A 2.2% 2.5% B 1.8% 2.2% C 2.5% 3.0% D 3.0% 3.2% E 2.6% 2.3% F 2.6% 2.7% Which test would you use to determine if the results obtained by the two methods agree within experimental error?