I am a 37 year old software consultant who is preparing for a machine learning certificate exam. The Statistics course here helps me clarifies bunch of basic concepts, e.g. sample distribution, sample proportion, central limit theorem, confidence interval, and so on. The course is very well designed and organized, and needless to say Mr. Khan's way of teaching always makes me comfortable and inspired. In addition, the AP exam for US high school students is also impressive. I learnt statistics in Grade 3 when I was in university, and I have to admit that these statistics concept becomes crystal clear to me only after I took the Khan academy course recently.
You are doing a great job to offer the excellent course online for free. I appreciate it very much.