(1) 2c P(X > = P(−2) + P(−1) + P(0) + P(1) + P(2) = 0.85 B1 1.1b 4th −2.3) Calculate probabilities from discrete distributions. (1) (4 marks) Notes Pearson Progression Step Q Scheme Marks AOs and Progress descriptor 3a 2k + + 0 + = 1 M1 2.1 4th k k Calculate 1.1b = 1, so = 0.25 (answer given). A1* 4k k probabilities from discrete distributions. (2) P(X1 + = 5) = P(X1 = 3 and = 2) + P(X1 = 2 and = 3) 2.4 4th 3b B1* X2 X2 X2 = 0 + 0 = 0 (answer given). Calculate probabilities from discrete distributions. (1) 2.5 4th 3c M1 A1 1.1b Calculate probabilities from A1 1.1b discrete distributions. (3) 3.4 3d P(1.3 + 3.2) = P(X1 + = 2) + P(X1 + = 3) M1 X1 X2 X2 X2 ⩽ ⩽
(1) 2c P(X > −2.3) = P(−2) + P(−1) + P(0) + P(1) + P(2) = 0.85 B1 1.1b 4th Calculate probabilities from discrete distributions. (1) (4 marks) Notes Q Scheme Marks AOs Pearson Progression Step and Progress descriptor 3a 2k + k + 0 + k = 1 M1 2.1 4th Calculate probabilities from discrete distributions. 4k = 1, so k = 0.25 (answer given). A1* 1.1b (2) 3b P(X1 + X2 = 5) = P(X1 = 3 and X2 = 2) + P(X1 = 2 and X2 = 3) = 0 + 0 = 0 (answer given). B1* 2.4 4th Calculate probabilities from discrete distributions. (1) 3c M1 A1 A1 2.5 1.1b 1.1b 4th Calculate probabilities from discrete distributions. (3) 3d P(1.3 ⩽ X1 + X2 ⩽ 3.2) = P(X1 + X2 = 2) + P(X1 + X2 = 3) M1 3.4
as_maths_statistics_unit_4_ms.docx