Decades: 1170s 1180s 1190s 1200s 1210s - 1220s - 1230s 1240s 1250s 1260s 1270s
Years: 1219 1220 1221 1222 1223 - 1224 - 1225 1226 1227 1228 1229
Births
Deaths
... one gets approximately a normal distribution. But for every normally distributed variable, the probability that it is negative is non-zero! How is it possible to ...