IAL Statistics 1 Discrete Random Variables exam questions

Exam-style questions on discrete random variables for Edexcel IAL Statistics 1 (WST01): probability distributions, E(X), Var(X) and the uniform case.

This resource covers the whole of Chapter 6 (Discrete Random Variables) of the Pearson Edexcel International A Level Statistics 1 course. All questions are original and written in the style of the WST01 paper — these are not reproduced past paper questions.

What’s covered

Probability distributions and probability functions
Using the fact that the probabilities sum to 1 to find an unknown
The cumulative distribution function
Expected value E(X) and variance Var(X)
E and Var of a linear function of X, such as E(aX + b)
The discrete uniform distribution and its mean and variance

How to use it

Works as homework, as consolidation across a sequence of lessons, or as revision before the WST01 paper. Finding an unknown in a distribution and then computing E(X) and Var(X) from it is the standard WST01 structure, so the questions are built in those linked stages.

What’s included

Question paper (PDF, printable)
Full worked solutions (PDF) — complete method, not just final answers
Questions arranged in increasing difficulty

Specification

Written for Edexcel International A Level Mathematics, Statistics 1 (WST01), Chapter 6. Also suitable for Edexcel A Level Mathematics 9MA0 statistics content and for legacy S1 courses.