The Environmental Protection Agency has determined that safedrinking water should, on average, contain no more than
1.3 mg/liter of copper. You are testing water from a new source,and take 31 water samples. The mean copper content in
your samples is 1.46 mg/l and the standard deviation is 0.18mg/l.
(a) Is there convincing evidence at the α = 0.05 significancelevel that the water from this source contains unsafe levels of
copper? (Do a 4-step process)
(b) Referring to your conclusion, what type of error may havebeen made? Describe the error in the context of this study.
(c) Describe two ways to increase the power of the test in part(a).
