Hi, for CM2A are we allowed to use this function to solve for phi or do they want to see the tables result (interpolated)?
You can use any calculator in the world (including Excel) to work out P[Z< number]. You do not need to use a printed table and linearly interpolate. However, for Paper A, I would be cautious to show my working if the number was negative, for example, P[Z< -0.543] = 1 - P[Z<0.543] and then use Excel. I would also not use ANY Excel s/sheet where I had typed anything at all before the exam clock has started. Weirdly, if you use a Casio (fx991-ES for example), the phi function is already in the circuit board, which is equivalent to having an Excel s/sheet ready set-up with just cell B1 saying "=norm.s.dist(a1,true)", ie ready to type 0.543 into Cell A1 and give an answer in B1. Yet, my understanding is that this second method would constitute a "pre-existing spreadsheet" - so you're actually better off with a Casio in this respect - a pre-existing calculator, I suppose :-D Good luck! John
