“John Tromp and Peter Österlund estimated the number of legal chess positions with a 95% confidence level at ( 4.822 ± 0.028 ) × 10^44, based on an efficiently computable bijection between integers and chess positions.”

%95 confidenece level? Did they make a poll?

Tldr Estimated total number of legal chess positions is (4.822 ± 0.028) * 10⁴⁴