There is no fixed size of samples that guarantees a result is statistically significant. How many samples are needed depends on the desired p-value among other

There is no fixed size of samples that guarantees a result is statistically significant. How many samples are needed depends on the desired p-value among other things, which in turn depends on prior assumptions, and on the quantities being measured. "Typically accepted sizes" are nothing but cargo cult science. That's precisely why psychologists take statistics classes as part of their education. I get that those aren't everyone's cup of tea, but people who don't even understand the basics have no business conducting and publishing studies. In fact, well-designed scientific studies typically start with a discussion of p-values, sample sizes, possible sources of biases, etc. If you don't see any mention of those in a study, you know you're looking at junk.