In: Statistics and Probability
3) As part of your work for an environmental awareness group, you want to test the claim that the mean amount of lead in the air in U.S. cities is less than 0.036 microgram per cubic meter. You find that the mean amount of lead in the air for a random sample of 56 U.S. cities is 0.039 microgram per cubic meter with a standard deviation of 0.069 microgram per cubic meter. At α = 0.01 what can be concluded about the claim?
Here, we conduct the T-test for one population mean as :
Hence, there is not enough evidence to claim that the mean amount of lead in the air in U.S. cities is less than 0.036 microgram per cubic meter at 1% level of significance.