The size distribution of U.S. families as estimated by the U.S. Bureau of Census is given in table below.
![99_ea5b4809-29e7-4705-980d-00255e4a2c44.png](https://secure.tutorsglobe.com/CMSImages/99_ea5b4809-29e7-4705-980d-00255e4a2c44.png)
a Calculate the mean and standard deviation of family size. Are these exact values or approximations?
b How does the mean family size compare to the median family size?
c Does the empirical rule hold for the family size distribution?