Hypothesis Testing for a t-test. Monitoring Lead in Air. Listed below are measured amounts of lead in micrograms per cubic meter or ug/m to the third power in the air. The EPA has established an air quality standard for lead of 1.5 micrograms per cubic meter or ug/m to the third power. The measurements shown below constitute a simple random sample of measurements recorded at bed 5 of the world trade center site on different days immediately following the destruction caused by the terriost attact of September 11, 2001. After the collapse of the two Word Trade Center building there was a considerable concern about the quality of 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 for 1.5 ug/m to the third power. Show all steps null and alternate hypothesis, diagram, critical value, test statistic. Reject or do not reject conclusion.