I do have a large dataset containing nearly a decade of particulate matter measurements. At the lower precision limit of the measuring instrument, there are values given like
< 8. For statistical analysis however, a defined value is needed.
What is the best possible way to deal with this?
- Replacing it as missing values?
- Replacing it by
- Assuming the mean value between something like
8; e. g.
Or is there a better solution, maybe considering the natural background value?
EDIT: I'd like to calculate the intra-day- and intra-year distribution, as well as searching for patterns by considering wind directiond and speed.