How to check normality of a binary data(True/False) for z proportion test? One of the three conditions that should be checked before conducting two-sampled z-test for proportions is "check for normality"(link for the source: https://vitalflux.com/two-sample-z-test-for-proportions-formula-examples/). But how can we check whether binary data is normal?

Any assumption about normality is totally violated for a binary variable: normal distributions take values on the entire real line, while binary variables take two values, and $2\ne\infty$. Consequently, that reference is wrong about this topic and likely makes mistakes on other topics, too, and I would not trust it.
