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How do you interpret "nested" standard deviational ellipse?

Question asked by LawDoug on Nov 3, 2015
Latest reply on Nov 10, 2015 by JDAcosta-esristaff

We would like to explore disparities in Tobacco retail locations in my county. Majority were surveyed by the local health department however, there were 16 that were not surveyed. We would like to use the surveyed location to explore the disparities however, we want to confirm that those that did not participate in the survey, are not located in areas that is potentially different from the area of those surveyed. To answer this question, I thought the best approach would be to calculate the mean centers and standard deviational ellipses ( at one standard deviation) to compare the distribution of surveyed v not surveyed. The mean centers of both, surveyed and not surveyed were within a 1/2 mile of each other however, the ellipse of the not surveyed was with in the ellipses of those surveyed. Because i am relatively new to the field, I just wanted to confirm that my interpretation of the "nested" ellipses results means that we can be confident that  the information collected from the survey "speaks" to the general landscape of tobacco retail in the county. ( see attachment for reference)