Assume that the differences are normally distributed. Complete parts (a) through (d) below. Observation 2 3 4 5 6 7 8 Xi 47.1 47.5 51.1 42.7 48.9 51.7 51.4 54.7 51.2 46.3 54.8 47.8 49.6 52.4 51.6 53.8 (a) Determine d; = X; - Y; for each pair of data. Observation 2 4 5 6 8 d; - 4.1 1.2 - 3.7 - 5.1 - 0.7 - 0.7 - 0.2 0.9 (Type integers or decimals.) (b) Compute d and sd. d= -1.55 (Round to three decimal places as needed.) Sd = (Round to three decimal places as needed.)