<p>You’re in quite a tough situation. I took AP Calc BC, AP Calc AB, and AP Stats all at the same time. Trust me, the Ti-89 is great for Calculus since it can solve functions, integrate, differentials,and derive which is mainly all of Calc for AB and BC. Though the Ti-89 can do stats functions, it requires a download from Texas instruments in order to get all the functions a Ti-84 plus has and more. Also the Ti-89 is much slower in user interface than the Ti-84 plus or Ti-83 plus meaning it takes quite a while to punch in the numbers and get to the desired functions for stats while the Ti84 or Ti83 (both the Ti84 and Ti83 are the same in functions except the ti84 is just faster has more ram more memory and more apps which are useless anyways) are much faster in getting to your functions for stats. Precious time on the AP test can cost you especially when you can use a calculator for the whole AP STATS test only. Though the Ti84 and Ti83 are faster they however cannot perform any to most of the advance calculus tenchinques like integrate and derive (you can but it requires alot of ingenuity with the graphs and if you do figure it out you can only get about half the answer which is the useless half of the answer) I suggest to get both the ti84 and ti89. If your strapped for cash go for the ti89 and download the stats package.</p>