Bar and bat mitzvah mean, literally, son and daughter of the commandment.. Bat mitzvah is Hebrew, while bar mitzvah, historically a much earlier ceremony, is Aramaic. The word bar is the Aramaic equivalent of the Hebrew ben (son of) .
In math, the mean is the average of a set of numbers. To determine the mean, add all numbers in a set and take this answer and divide it by how many numbers are in the set. Continue Reading.
In fact even in mathematics there are different averages or means and this one is more properly called the arithmetic mean. The quantity obtained by adding the largest and smallest values and dividing by 2, statisticians call the midrange. There are times however that this is called the mean.