A white paper presents a study of contamination in landfills containing construction waste and demolition waste. Leachate samples were taken from a test site. Of every 42 samples, 26 contain detectable levels of lead, 41 of arsenic, and 32 of chromium. a) verify the applicability of the statistical techniques studied, b) according to literal a, determine if there is evidence that 70% of the test area contains detectable levels of arsenic and chromium, b) determine if there is evidence to indicate that more than half of the test site area has no detectable levels of any contaminant.