1 2 During 2012 Texas had listed on FracFocus an industry fracking disclosure site nearly 6 000 oil and gas wells in which the fracking methodology was used to extract natural gas Fontenot et al 2013 reports on a study of 100 private water wells in or near the Barnett Shale in Texas There were 91 private wells located within 5 km of an active gas well using fracking 4 private wells with no gas wells located within a 14 km radius and 5 wells outside of the Barnett Shale with no gas well located with a 60 km radius They found that there were elevated levels of potential contaminants such as arsenic and selenium in the 91 wells closest to natural gas extraction sites compared to the 9 wells that were at least 14 km away from an active gas well using the fracking technique to extract natural gas I a Identify the population that is of interest to the researchers b Describe the sample c What characteristics of the population are of interest to the researchers d If the sample measurements are used to make inferences about the population characteristics why is a measure of reliability of the inferences important