In elementary school when I was taught how to round numbers to a whole number, I was taught that if the last digit ends in 0, 1, 2, 3, or 4, round down to ‘0’. Otherwise round up to the next digit.
But later on, I was told that this introduces bias and that there are different techniques to deal with it.
So I want to believe that it does cause bias because people much smarter than me in this have developed these techniques to reduce it.
But I can’t convince myself of it. Can someone explain this to me like I’m a 5 year old?