Sorry if this is a really basic question. A friend was mentioning that he was going to put a small windfall into stocks since the stock market returns 11% over time. He can't afford to lose any money but with some of those 20+ percent drops in the last 20-25 years, how can it really average that much? But googling a&p average returns over 10-20 years does say that.
Is this really true and would it be risky for him to essentially put everything into a standard index fund. It just doesn't seem safe but he is arguing the numbers are clear