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IB Maths AA SL 4.7 Discrete Random Variables

IB Maths AA SL 4.7 Discrete Random Variables
IB Mathematics: analysis and approaches guide, first assessment 2021

Practise completing discrete probability distributions and calculating probabilities, mode, expectation and variance while enforcing that every probability is valid and totals one.

How this is tested

  • use the sum of table probabilities or a stated expectation to determine an unknown parameter
  • add the appropriate probability masses for an event and use a complement when shorter
  • calculate E(X) and Var(X), then interpret expectation or compare mode and median in context

Question 1

[Maximum number: 6]

The discrete random variable X has the following probability distribution:

Table for Question 1 — IB Maths AA SL

Question 1(a)

(a)

Find the value of k.

[ 2 ]

Question 1(b)

(b)

Find P(X>1.5).

[ 2 ]

Question 1(c)

(c)

Find E(X).

[ 2 ]