Each year, Forbes magazine compiles a list of the 400 richest Americans. As of September 17, 2008,

Question:

Each year, Forbes magazine compiles a list of the 400 richest Americans. As of September 17, 2008, the top 10 on the list are as shown in the following table.
Person Wealth ($ billions)
William Gates III ............57.0
Warren Buffett .............50.0
Lawrence Ellison .............27.0
Jim Walton ................23.4
S. Robson Walton .............23.3
Alice Walton ...............23.2
Christy Walton & family .........23.2
Michael Bloomberg ...........20.0
Charles Koch ..............19.0
David Koch ...............19.0
a. Mean.
b. Median.
c. Mode(s).
For the mean and the median, round each answer to one more decimal place than that used for the observations.