Various sources provide different earthquake data, but assume that for a recent 41-year period in the United States, there were 268 earthquakes measured at 6.0 or higher on the Richter scale (based on U.S. Geological Survey data).
a. Find the mean number of earthquakes per year.
b. Find the probability that in a given year, there is at least one earthquake in the United States that measures 6.0 or higher on the Richter scale.
c. Is it unlikely to have a year without any earthquakes that measure 6.0 or higher on the Richter scale? Why or why not?