A-Level MathematicsYear 2021Q3
10 3. The discrete random variable X has probability distribution x −3 −2 −1 0 2 5 P(X = x) 0.3 0.15 0.1 0.15 0.1 0.2 (a) Find E(X ) (1) Given that Var(X ) = 8.79 (b) find E(X 2) (2) The discrete random variable Y has probability distribution y −2 −1 0 1 2 P(Y = y) 3a a b a c where a, b and c are constants. For the random variable Y P(Y 0) = 0.75 and E(Y 2 + 3) = 5 (c) Find the value of a, the value of b and the value of c (5) The random variable W = Y − X where Y and X are independent. The random variable T = 3W – 8 (d) Calculate P (W > T) (4) _____________________________________________________________________________________ _____________________________________________________________________________________ _____________________________________________________________________________________ _____________________________________________________________________________________ _____________________________________________________________________________________ _____________________________________________________________________________________ _____________________________________________________________________________________ _____________________________________________________________________________________ _____________________________________________________________________________________ _____________________________________________________________________________________ _____________________________________________________________________________________ _____________________________________________________________________________________
Paper Source:8FM0_23_que_20211109.pdf
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Exam Specification Info
This question is part of the UK A-Level Mathematics syllabus. In the actual exam, structured questions typically require linking specific keywords to gain full marks. Applaa helps you drill these topics.
Syllabus levelAdvanced Level (A-Level)
SubjectMathematics
Official MarksVariable (2–6 marks)