Table 12. Characteristics of numeric variables for the file (cement92.dat) containing the annual
hydraulic cement production estimates from the U.S. Bureau of Mines
| Number of | Minimum | Maximum | ||
| Variable | observations | value | value | Mean |
| COUNTRY | 4685 | 4.000 | 894.000 | 433.064 |
| YEAR | 4685 | 1950.000 | 1992.000 | 1972.854 |
| QUANTITY | 4685 | 0.000 | 526530.000 | 12758.425 |