Americium 241 (241Am) is a radioactive material used in the manufacture of smoke detectors. The article “Retention and Dosimetry of Injected 241Am in Beagles” (Radiation Research [1984]: 564– 575) described a study in which 55 beagles were injected with a dose of 241Am (proportional to each animal’s weight).

Skeletal retention of 241Am (in microcuries per kilogram)

was recorded for each beagle, resulting in the following data:

0.196 0.451 0.329

a. Construct a frequency distribution for these data, and draw the corresponding histogram.

b. Write a short description of the important features of the shape of the histogram.