Monitoring Lead in Air Listed below are measured amounts of lead (in micrograms per cubic meter or mg m3) in the air. The Environmental Protection Agency has established an air quality standard for lead: 1.5 mg m3. The measurements shown below were recorded at Building 5 of the World Trade Center site on different days immediately following the destruction caused by the terrorist attacks of September 11, 2001. After the collapse of the two World Trade Center buildings, there was considerable concern about the quality of the air. Use a 0.05 significance level to test the claim that the sample is from a population with a mean greater than the EPA standard of 1.5 mg m3. Is there anything about this data set suggesting that the assumption of a normally distributed population might not be valid?

5.40 1.10 0.42 0.73 0.48 1.10