Question 1 - A-Level Maths

Exam Board	CAIE
Module	S2 (Statistics 2)
Year	2015
Session	June
Topic	Linear combinations of normal random variables
Type	Pure expectation and variance calculation

1 The independent random variables \(X\) and \(Y\) have standard deviations 3 and 6 respectively. Calculate the standard deviation of \(4 X - 5 Y\).