GCSE Maths - stratified samplying help?
Hey, I have real trouble actually remembering the equation, and where every number is supposed to go - can someone give me some simple formula to work out stratified samplying.
Also, I am completely clueless with this question, please explain your answer::
http://store.aqa.org.uk/qual/gcse/qp-ms/AQA-33011H-W-QP-NOV07.PDF
It is QUESTION 14 - please help me.