Statistics (12th Edition)

df = n - 1 = 16 - 1 = 15 $t_{α/2} = 0.05$ From student's t distribution table, we have: $t_{0.05} = 1.753$ $E = 1.753 . \frac{8}{\sqrt 16} = 1.753 . 2 = 3.506$ Confidence interval will be: $\bar d - E = -7 - 3.506 = -10.506$ $\bar d - E = -7 + 3.506 = -3.494$