Assume that the differences are normally distributed. Complete parts (a) through (d) below. Observation 1 2 3 4 5 6 7 8 Xi 41.3 51.7 51.8 49.8 44.6 45.9 48.6 47.2 45.2 50.4 53.1 53.7 46.1 49.2 50.2 48.9 (a) Determine di = X; - Y, for each pair of data. Observation 1 5 6 7 8 (Type integers or decimals.) (b) Compute d and sa. d=(Round to three decimal places as needed.) Sa =(Round to three decimal places as needed.) (c) Test if Ha 0 H1: Hd >O Hy : Hd