+ dredge output response in MuMIn

[binoink]

Can someone please tell me what the + output means in the dredge function output for lmer in MuMIn package? This is for a categorical variable. I cannot find anything online and i'm going nuts. Similarly, how to interpret.

input code is

library(MuMIn) ## This is the package for multimodel comparisions 
library(lme4)  ## This is the package to do mixed models using lmer()
## This is the model with Bowl as random effect
fm1 <- lmer(Vol ~ Density+biomass+stemWid+row2+(1|Box),data=Bdata,na.action = "na.fail")
dd1 <- dredge(fm1)

where all variables are continuous except for Density (2 levels Low or high) and row (4 levels - 1st, 2nd, 3rd, 4th; this variable should be ordinal and I am struggling to specify it as such as well).
my out put looks like this where density and row2 are get "+" and I cannot figure out how to interpret that.

Global model call: lmer(formula = Vol ~ Density + biomass + stemWid + row2 + (1 | 
    Box), data = Bdata, na.action = "na.fail")
---
Model selection table 
   (Intrc) bimss Dnsty row2  stmWd df  logLik  AICc delta weight
8  -0.8677 1.524     +    +         8 -95.699 213.7  0.00  0.373
6  -2.4380 1.614          +         7 -98.125 214.9  1.26  0.199
16 -1.2290 1.304     +    + 0.5109  9 -94.627 215.4  1.78  0.154
15  5.3570           +    + 1.6620  8 -96.762 215.8  2.13  0.129
14 -2.8900 1.439          + 0.4144  8 -97.088 216.4  2.78  0.093
7  12.8100           +    +         7 -99.460 217.6  3.93  0.052
Models ranked by AICc(x) 
Random terms (all models): 
‘1 | Box’

[jcblum]

Hi! Welcome!

I’m afraid I don’t have an answer for you, but I have a couple of suggestions to hopefully help you get an answer faster:

1. This doesn’t sound like a question about the RStudio IDE, so I think it will find a more interested and knowledgeable audience in a different category. I recommend moving the question to Machine Learning and Modeling.

2. Can you please format your code as code? We ask people to do that around here because it’s difficult to read code that’s not formatted correctly, and special characters can accidentally trigger other types of automatic formatting (like how your comments turned into headings). Just edit your post (little pencil icon at the bottom), select all your code, and click the </> button at the top of the editing box.

[michaellee]

Hi - Did you ever figure this issue out?

I cannot find the answer anywhere either.

[Fer]

It means that the term is included in the model.