Active nuclear power plants. The U.S. Energy Information Administration monitors all nuclear power plants operating in the United States. The table below lists the number of active nuclear power plants operating in each of a sample of 20 states.

a. Find the mean, median, and mode of this data set.

State Number of Power Plants State Number of Power Plants Alabama 5 New Hampshire 1 Arizona 3 New York 6 California 4 North Carolina 5 Florida 5 Ohio 3 Georgia 4 Pennsylvania 9 Illinois 11 South Carolina 7 Kansas 1 Tennessee 3 Louisiana 2 Texas 4 Massachusetts 1 Vermont 1 Mississippi 1 Wisconsin 3

b. Eliminate the largest value from the data set and repeat part

a. What effect does dropping this measurement have on the measures of central tendency found in part a?

c. Arrange the 20 values in the table from lowest to highest. Next, eliminate the lowest two values and the highest two values from the data set, and find the mean of the remaining data values. The result is called a 10%
trimmed mean, since it is calculated after removing the highest 10% and the lowest 10% of the data values.
What advantages does a trimmed mean have over the regular arithmetic mean?