The vector PQ is Q-P = (2, 1). The vector SR is R-S = (2, 2). One is not a multiple of the others, so the vectors are not parallel. In a parallelogram, these vectors would be identical. PQRS is not a parallelogram.
The regression equation: y = m x + b m = ( 57 - 50 ) / ( 178 - 168 ) = 7 / 10 = 0.7 50 = 0.7 * 168 + b 50 = 117.6 + b b = 50 - 117.6 b = - 67.6 y = 0.7 * x - 67.6 The graph is in the attachment. The weight of supermodel who is 171 cm tall: y = 0.7 * 171 - 67.6 = 119.7 - 67.6 = 52.1 kg
