Does anyone else often see people say or use 1084 as the standard for full credibility at auto companies? I was wondering why it seems that a lot of people say 1084 instead of 1082. After all (1.645/0.05)^2 = 1082 where 1.645 is the z-score in your normal table corresponding to the 90% percentile and 0.05 being the tolerable error you accept.