Consider the study for comparing two methods for determining the iron content in ore samples described in Example 9.5-3. A total of 12 ore samples are analyzed by both methods, producing the paired data that yield D = −0.0167 and SD = 0.02645.

Is there evidence that method B gives a higher average percentage than method A?

Test at α = 0.05, compute the p-value, and state any needed assumptions.