Balls from urns, mean, expectation, variance, sum of random variable, indicator function.
[STEP III 1988 Question 16 (Probability and Statistics)]
Underground Mathematics: Selected worked STEP questions
STEP Question database
University of Cambridge Mathematics Faculty: What do we look for?
University of Cambridge Mathematics Faculty: Information about STEP
University of Cambridge Admissions Office: Undergraduate course information for Mathematics
Stephen Siklos' "Advanced Problems in Mathematics" book (external link)
MEI: Worked solutions to STEP questions (external link)
OCR: Exam board information about STEP (external link)
AMSP (Advanced Maths Support programme): Support for University Admission Tests (external link)
