


Earthquakes the the Poisson Distribution 

Content Material
 Student Directions:
 Open and print student worksheet  EarthquakePoisson.doc.
 Go to the U.S. Geological Survey Earthquake Hazards Program at http://earthquake.usgs.gov, click on "Research and Monitoring", select "Scientific Data", and then "QED List  Last 30 Days".
 Copy and Paste the data, including the column titles, into a Microsoft Excel spreadsheet, starting in cell B1. Note: The data should paste line by line just as it is on the website. If the date pastes into one cell, then undo the paste, choose Paste Special from the Edit menu, and select the text option.
 Type the following function into cell A2: =VALUE(MID(B2,10,2)). The MID formula extracts 2 characters in the middle of cell B2, starting at position 10. Here, that is the hour that the earthquake occurred in UTC (Coordinated Universal Time). The VALUE function converts the characters from text to a numerical value so that we may do arithmetic operations. Highlight cell A2, then drag the corner to fill column A with the formula.
 Create a set of bin values from 0 to 23 (hours) to the right of the data, then make a frequency distribution and histogram using Excel.
 Is our sample is representative of the population? Why or why not?
 Find the mean and standard deviation of the sample using Descriptive Statistics in Excel.
 Assuming that the distribution is indeed Poisson, find the probability (using a calculator or the internet) to four decimal places that the number of earthquakes in a randomly selected day is
 0
 25
 50
 75
 at least 10
 at most 40.
 Referenced URLs:

