search for: substratum

...am having difficulty interpretive the multiple regression output. I would like to know what it means when one of the factors is assigned as the intercept? In my data I am looking at the relationship between environmental parameters and biological production. One of my variables in the analysis is substratum type and gravel is identified as the intercept and the P-value is significant,... Does this mean that I can talk about the relationship which it has with production as being significant or because it is the intercept can I not use it because it has been selected and used as the basis for the relat...

Dear R users, I face to a nested pattern and despite the numerous examples in the help I am still confused. I sampled bugs in different habitats within sites which were within rivers themselves within different regions. The habitat correspond to different substrata (not systematically present in all sites). For rivers and sites, I have environemental variables (e.g. altitude and slope of