CASE STUDIES IN BIOMETRY: Chapter 3. Prediction Models for Personal Ozone Exposure Assessment David Wypij and L.-J. Sally Liu The file ch3a.dat includes the validation data collected at the stationary ambient monitoring site. The variables are: 1. Date, in MM/DD/YY format, DC 2. 12-hour average daytime continuous ozone concentration, X , 1 DP 3. 12-hour average daytime passive ozone concentration, X , 1 NC 4. 12-hour average nighttime continuous ozone concentration, X , and 1 NP 5. 12-hour average nighttime passive ozone concentration, X . 1 All ozone measurements are given in units of ppb. A single missing value is encoded as a period.