1. Is it true that two-thirds of observations are within one standard deviation of the mean? What about the rule of thumb that 95% of observations are within 2 standard deviations of the mean?

1. Should you play the lottery?This is a reverse case of the median and mean: the median is to lose; the mean is better, but you still lose. On the other hand, buying a lottery ticket does give you the opportunity to dream about what you'd do with all the money: some economists say that that is why people pay to play the lottery.

1. Is it better to present means and standard deviations or median and interquartile range?