Glossary N
Nonparametric Tests are all studies involving ranked data, i.e., data that can be put in order and used when there is no assumption that the population has a normal distribution or when the population is known to have low and high values and valuable in detecting population differences when certain assumptions are not satisfied.
A Nonroad mobile sources is a Mobile sources not found on roads and highways (e.g., airplanes, trains, lawn mowers, construction vehicles, farm machinery).