When I’ve run the model with all the ethnic data in place, the analysis tells me that all the variables but AA voters introduce noise. In other words, using only AA voters, I get the highest R-squared value.

But, California has a lot of Latino voters, and that increases the diversity and may have a big impact there. So, when I rerun the model with all the updated data, I’ll put all the variables back in and see if California changes.

I’m puzzled why your model, purportedly based on demographics, shows Sanders winning in California, which is a minority majority state. Sure, independents can participate in the Democratic primary, and the black population approximates the national average, but Clinton has so far done well with Latinos, and the jungle primary is expected to advance two women, both Democrats, neither necessarily white, to the general election to replace Barbara Boxer.

(Apropos of nothing: I’ve voted for Harris, of course, and will again. I’ve contributed to Sanchez, and received as a consequence a couple of mildly risqué Christmas cards.)

Not quite correct. Motor voter. You’re registered when you go in to the dmv for a license, idea, or learners permit. If you don’t go into the dmv you have to register yourself.