It’s about 300 samples for an estimate of the distribution with a 95% confidence iirc. That’s assuming the samples are representative (unbiased) and 95% confidence doesn’t mean it’s within 95% of reality, but that 5% of tests run in such a way would be expected to be inaccurate (and there’s no way of knowing for sure which one this particular sample is because even a meta study will have such an error rate, though you can increase the confidence with more samples or studies, just never to 100% unless you study every possible sample, including future ones).
It’s about 300 samples for an estimate of the distribution with a 95% confidence iirc. That’s assuming the samples are representative (unbiased) and 95% confidence doesn’t mean it’s within 95% of reality, but that 5% of tests run in such a way would be expected to be inaccurate (and there’s no way of knowing for sure which one this particular sample is because even a meta study will have such an error rate, though you can increase the confidence with more samples or studies, just never to 100% unless you study every possible sample, including future ones).