How to determine the fixed and random effect using linear mixed effect model in R studio?

[maudibawakemana]

Hi all,

I would like to investigate the variation of eye size among species and among type using linear mixed model.
However, I am a little bit confuse to determine whether to be random effect and fixed effect. I tried to use this model: lmer(Eyesize ~ Species + (1|Type) in R studio

this is my code

library(lme4)
library(lmerTest)
library(multcomp)

example_data <-read.csv("EXAMPLE 1.csv", h= TRUE)
head(example_data)
result = lmer(Eyesize ~ Species + (1|Type), data=example_data)
summary(result)

You can get my data here: data

I got the result of analysis like this

I cannot get the analysis result for species A.
Could anyone help me about this?
I cannot determine the fixed effect and random effect in this analysis.
I need help.

Thanks

[startz]

I'm not sure whether this helps, but in the fixed effects model the intercept is the fixed effect for group A.

[maudibawakemana]

does it mean my formula was wrong?

[startz]

Not wrong. You have three groups and you estimate three parameters.