Q. 2.145 - Elementary Statistics

Question

PCBs and Pelicans. Polychlorinated biphenyls (PCBs), industrial pollutants, are known to be carcinogens and a great danger to natural ecosystems. As a result of several studies, PCB production was banned in the United States in 1979 and by the Stockholm Convention on Persistent Organic Pollutants in 2001. One study, published in 1972 by R. W. Risebrough, is titled "Effects of Environmental Pollutants Upon Animals Other Than Man" (Proceedings of the 6ed Berkeley Symposium on Mathematics and Statistics, VI, University of California Press, pp. 443-463). In that study, 60 Anacapa pelican eggs were collected and measured for their shell thickness, in millimeters (mm), and concentration of PCBs, in parts per million (ppm). Following is a relative-frequency histogram of the PCB concentration data.

Step-by-Step Solution

Answer

The distribution is symmetric.

Step 1: Given Information

To determine whether the given graph is symmetric, right-skewed, or left-skewed.

Step 2: Explanation

Consider the given graph:

If the shape of any distribution is divided into two parts, one of which is the mirror image of the other, the distribution is said to be symmetric.

The graph in question cannot be divided into two equal halves, one of which is a mirror image of the other.