Getting 37/40 should secure a band 6 but don't overanalyse it as short answers require specificity and conciseness and who knows how they mark it. But honestly your splits can look at 18, 35, 16, 16- just going at worst - thats 85 which is band 6. So you should but essay questions especiallly the first one required a lot of stats and information. Me personally i know i got 18 in multies just can't remmeber only one of my solutions so likely split is 18, 35, 18, 16 which is 87. If you think you smashed short answer which would singifncantly boost your mark you are looking at a range of 87-92 if you did well in essays as well.