In a study of contamination at landfills containing construction and demolition waste, 42 leachate specimens were tested for the presence of several contaminants. Of the 42 specimens, 26 contained detectable levels of lead, and 32 contained detectable levels of chromium. Is it possible, using the methods of this section, to find a 95% confidence interval for the difference between the probability that a specimen will contain a detectable amount of lead and the probability that it will contain a detectable amount of chromium? If so, find the confidence interval. If not, explain why not.