Earthquake aftershock magnitudes. Seismologists use the term ‘‘aftershock'' to describe the smaller earthquakes that follow a main earthquake.
Following the Northridge earthquake on January 17, 1994, the Los Angeles area experienced 2,929 aftershocks in a three-week period. The magnitudes (measured on the Richter scale) for these aftershocks were recorded by the U.S. Geological Survey and are saved in the EARTHQUAKE file. A MINITAB relative frequency histogram for these magnitudes is shown below.
(a) Estimate the percentage of the 2,929 aftershocks measuring between 1.5 and 2.5 on the Richter scale.
(b) Estimate the percentage of the 2,929 aftershocks measuring greater than 3.0 on the Richter scale.
(c) Is the aftershock data distribution skewed right, skewed left, or symmetric?
