=+and can also result in fines levied by the federal government. As required by government regulation, researchers continually monitor pollution levels. In the most recent test of pollution levels, 121 air samples were collected.

The dust particulate levels must be reported to the federal regulatory agencies. In the report sent to the federal agency, it was noted that the mean particulate level = 57.6 micrograms/cubic liter of air, and the 95% confidence interval estimate is 52.06 mg to 63.07 mg. A graph of the distribution of the particulate amounts was also included and is shown below.

0 20 40 60 80 100 20 15 10 5

0 Particulates (in micrograms per cubic liter of air)

Number of Air Samples