The data set available here contains masses for 100 circulating U. S. pennies. All pennies in these data sets were minted between 1962 and 1981, a period during which a penny’s composition was 95% copper and 5% zinc with a reported nominal mass of 3.11 g. Some pennies minted in 1982 and all pennies minted from 1983-present are 99.2% zinc (as the core) and 0.8% copper (as a coating), with a reported nominal mass of 2.5 g. The data set is available as an Excel file.

File: penny

One use of the data is shown in the following histogram and superimposed normal distribution curve assuming that μ and σ^{2} for the population are equivalent to *X* and *s*^{2} for the sample. The total area of the histogram’s bars and the area under the normal distribution curve are equal.