CAIE A Level Mathematics 9709 · Discrete random variables

Discrete random variables: calculation question

2 marksChallenge

A discrete random variable $X$ has $\mathrm{E}(X) = 2$ . A second variable is defined by $Y = 5X - 6$ .

(a)
Find $\mathrm{E}(Y)$ .
[2]

Work it out, then check it

Your working is checked step by step against the answer key, with method marks, units and carried-forward errors handled the way a mark scheme handles them.

Answer this and get it marked, free

Free account, no card. Three marked written answers a day on the free plan.

How this question is marked

2 marks. Method marks are awarded for correct working even if the final answer is wrong, and a later part can still score if it correctly uses an earlier wrong answer.

More Discrete random variables questions

3 marks · Each time a machine is switched on it starts correctly with probability 90\%, independently of every other attempt. The random variable X…
2 marks · The discrete random variable X has the following probability distribution: x 1 2 3 4 P(X = x) frac110 frac410 frac410 p Given that the…
2 marks · The discrete random variable X has the following probability distribution, where p is an unknown probability: x 1 2 3 P(X = x) 1/10 2/10 p…
2 marks · A factory produces light bulbs. The probability that a bulb is defective is 0.25. A quality inspector selects a random sample of 20 bulbs…
2 marks · A machine produces components independently, and each component is faulty with probability 40\%. A sample of 100 components is taken, and…
3 marks · The discrete random variable X has the following probability distribution: x 4 3 7 P(X=x) 1/10 4/10 5/10 Find E(X).

All Discrete random variables questions

Written by Markquill to follow the Cambridge International syllabus. Markquill is independent and is not affiliated with or endorsed by Cambridge International.