IB Maths AA SL AA 4.4 Probability distributions questions

Exam-style questions in the shape of Paper 1 and Paper 2, with full markschemes. Read the markscheme, or type, photograph or draw your answer and get it marked.

Paper

Paper 1, no calculator Paper 2, calculator

Difficulty

Easy Medium Hard

Question 1

Paper 1, no calculatorHard6 marks

In a production run, the number of packets with faulty seals is modelled by $X\sim B(n,p)$ where $n$ and $p$ are unknown. The mean of $X$ is $3$ and its variance is $2.1$

(a)

Determine $n$ and $p$

[4]

(b)

In a separate check, an inspector selects 10 packets without replacement from a lot of 20 packets, of which exactly 6 have faulty seals. A supervisor uses the values of $n$ and $p$ from part (a) to model the number of faulty packets in the check. Comment on whether this is appropriate.

[2]