In the $1928-2020$ period, the S&P $500$ had average annual returns of $7\mathrm{.}8\%$ with a standard deviation of $19\mathrm{.}3\%.$ In the more recent and shorter period of $2011-2020,$ the S&P $500$ had average annual returns of $12\mathrm{.}2\%$ with a standard deviation of $12\mathrm{.}1\%.$ Based on these number, what conclusions can be drawn? The S&P $500$ performed better in the $2011-2020$ period versus the $1928-2011$ period, but it was more volatile. The S&P $500$ performed better in the $2011-2020$ period versus the $1928-2011$ period, and it was also less volatile. For an investor planning to invest in an ETF tracking the S&P $500$ over the next $40$ years it would be more likely to obtain average annual returns of $12\mathrm{.}2\%$ than $7\mathrm{.}8\%.$ On average, the S&P $500$ performed better in the $1928-2011$ period than in the $2011-2020$ period