You do NOT need a statistics class. A statistics class will go way above and beyond. Statistics is the easiest part of the MCAT and can be learnt by yourself.
Also, statistics is a co-subject rather than an independent subject on the MCAT. What I mean is that questions on the MCAT requiring statistical reasoning will occur alongside one or more of the natural or social sciences. So a lot of practice questions that you will do in natural or social sciences will automatically build up statistical reasoning skills.
On a final note, contrary to popular belief, the psych/soc section is NOT as statistics heavy as everyone makes it out to be. The B/B and C/P sections have fewer but harder statistical reasoning questions. So even though statistics does show up slightly more in the psych/soc section, a lot of it is just simple charts and graphs.