Psychology A LevelWatch
It depends on which exam board you're on. I've currently just finished the AS year of the new spec AQA A syllabus and the maths content isn't too bad. It's just measures of central tendency (median, mode, range) and measures of dispersion (mean, standard deviation) you also need to know a little bit of statistical knowledge, such as the sign test, be able to identify correlation and plot graphs. That's pretty much it, the maths is basically GCSE standard.