Lesson 2: Using Standard Deviation, part 2

Do cities closer to the ocean have more consistent temperatures?

Grade Level : 9-12

Background needed:

This lesson is planned as a follow-up to Using Standard Deviation, part 1. The student should understand how to use the standard deviation and percentage error to decide if a set of numbers are consistent or not.


  1. The student will use the Internet to gather temperature data from 3 cities.
  2. The student will calculate the standard deviation and percentage error of the gathered temperatures.
  3. The student will prove or disprove her hypothesis on the basis of these statistics.


  1. Access to the Internet and Netscape software.
  2. Previously set bookmark on the Netscape at the following URL for
    the weather report for Galveston, TX:
  3. Scientific calculator


To prove the hypothesis , gather the temperatures from 3 cities over a period of 2 weeks. The cities should lie in a fairly straight line from the ocean , be reasonably close to one another, and have no other major bodies of water nearby. This example will use Galveston, Houston, and Dallas, Texas; but a combination like Charleston and Augusta ,South Carolina combined with Atlanta, Georgia would also work.

To find the temperatures, log on to the Internet and Netscape, then go to the National Weather Service information provided by the University of Michigan Weather Underground by clicking on the bookmark called Weather Conditions for SEA. Once there, scroll down until you reach the temperature, humidity, wind, air pressure, and weather for Galveston. Note the time that these recordings were taken. It is important that the readings for the next 2 weeks be taken at the same time in all three cities.

To get to the next city, scroll to the searchable index box and type in the 3 letter airport code for that city. Galveston is gls, Houston is hou and Dallas is dal. If you don't know this code, the index will accept the full city name, go to that location, and then tell you the code for future reference.

At the end of two weeks, students divide into 3 groups, one for each city; and find the mean, standard deviation, and percentage error of their city's temperatures. If the hypothesis is true, Galveston should have the most consistent temperatures, followed by Houston and then Dallas. Discuss the effect consistent and inconsistent weather has on a city. Possibly affected industries would be housing, tourism, retail clothing, landscaping, and public utilities. In closing the lesson remind the students that mathematics and specifically statistics ARE good for something, and this is just one of many examples!