I am new to RStudios, and am struggling to understand why I am getting an "empty model" error with my panel data. Because it is almost certainly a statistical concept error of mine, I created a simplified version of what I am trying to do to hopefully make it easier to tell what I'm getting wrong.
I am trying to perform a simple regression:
3 students, with 3 GPAs over 3 years, and a binary variable for Female/Male (0/1).
The idea would be to regress GPAs on sex to find out what effect being a Male has on GPA over time, controlling for each student.
However, when I run the code, I get "empty model" error. Below is the image with all the data, and the code I attempted, with the error as well:
I am certainly structuring the data incorrectly, but I can't figure out why.