Monitoring Dioxin Listed below are measured amounts of dioxin in the air at the site of the World Trade Center on the days immediately following the terrorist attacks of September 11, 2001. Dioxin includes a group of chemicals produced from burning and some types of manufacturing. The listed amounts are in nanograms per cubic meter (ng m3) and they are in order with the earliest recorded values at the left. The data are provided by the U.S. Environmental Protection Agency.

0.161 0.175 0.176 0.032 0.0524 0.044 0.018 0.0281 0.0268

a. Find the mean of this sample.

b. Find the median.

c. Find the standard deviation.

d. Find the variance.

e. Find the range.

f. Construct a 95% confidence interval estimate of the population mean.
g. The EPA uses 0.16 ng m3 as its “screening level,” which is “set to protect against significantly increased risks of cancer and other adverse health effects.” Use a 0.05 significance level to test the claim that this sample comes from a population with a mean less than 0.16 ng m3.
h. Is there any important characteristic of the data not addressed by the preceding results? If so, what is it?