The independent random variables XXX and YYY are defined as X∼N(50,42)X \sim N(50, 4^2)X∼N(50,42) and Y∼N(40,52)Y \sim N(40, 5^2)Y∼N(40,52). The random variable AAA is defined as
A=3X−2Y A = 3X - 2Y A=3X−2YFind:
E(A)E(A)E(A)
Var(A)Var(A)Var(A)
The random variables X1,X2,X3,X4,X5X_1, X_2, X_3, X_4, X_5X1,X2,X3,X4,X5 are independent of one another and of XXX and YYY, and each has the same distribution as XXX. The random variable BBB is defined as
B=∑i=15Xi B = \sum_{i=1}^{5} X_i B=i=1∑5XiFind P(B>4A)P(B > 4A)P(B>4A).
390 exam-style questions on OCR (MEI) A Level Maths 2.4 Probability Distributions, covering 2.4.1 Recognise binomial situations, 2.4.2 Probability of success p, 2.4.3 Calculate binomial probabilities, 2.4.4 Mean of the binomial distribution, 2.4.5 Expected frequencies for binomial, 2.4.6 Probability functions and discrete random variables, 2.4.7 Numerical probabilities for a simple distribution, 2.4.8 Normal distribution as a model (A-level only), 2.4.9 Shape of the Normal curve (A-level only), 2.4.10 Linear transformation and standardising (A-level only), 2.4.11 Symmetry and inflection of Normal curve (A-level only), 2.4.12 Calculate probabilities from a Normal distribution (A-level only), 2.4.13 Model with probability distributions, and 2.4 Probability Distributions. Each one has a worked solution and a mark scheme showing where the marks go.