IB Maths AA SL 4.7 Discrete random variables Question Bank

Practise IB Mathematics SL/HL 4.7 by applying discrete random variables methods to exam-style questions.

Exam points

identify the mathematical structure, variable or representation
select and apply the correct theorem, formula or algorithm
check the result using units, domain, graph or logical reasoning

[Maximum number: 5]

A supermarket analyses the shopping habits of its customers.
The number of times, X, each customer visits the supermarket in a week is given by the following probability distribution.

Table for Question SL 4.7—Discrete random variables question 1 — IB Maths AA SL

(a)

Find the value of a.

[ 3 ]

summing probabilities and equating to 1

\begin{aligned} & 1.5 a+2 a+0.281+a+0.026=1 \\ & (a=) 0.154 \end{aligned}

(b)

Find the mean of X.

The manager wants to know why customers come to their supermarket. They survey the first 50 customers to arrive at the supermarket on a particular day.

[ 2 ]

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SL 4.7—Discrete random variables question 1

Question (a)

Question (b)