With 12 paired differences, x-bar_d = 2.5, s_d = 4.0. Test H0: mu_d = 0 vs Ha: mu_d > 0.
The t statistic and a rough p-value are:
- Acheck_circle
t = 2.17, p ≈ 0.026
- B
t = 0.625, p ≈ 0.27
- C
t = 6.25, p < 0.001
- D
t = -2.17, p ≈ 0.974
Explanation
t = 2.5/(4/sqrt(12)) = 2.5/1.155 = 2.165. Upper-tail p with df = 11 is about 0.026.