What is the middle number in set of data?
If there are an odd number of elements in the set, there is a middle number which is the median.
If there are an even number of elements in the set, the median is the mean of the middle two numbers.
A number does not have a quartile, a set of data does. The lower quartile of a set of data set is a value, in the data set, such that a quarter of the date set are smaller and three quarters are larger. The upper quartile is defined similarly. The middle quartile, better known as the median, divides the data set in two.
Average - the central tendency of a data set is a measure of the "middle" or "expected" value of the data set (mean, median, mode) Layman's terms - the average of a math problem is the middle number, usually found by taking the highest number and subtracting the lowest number, or taking the highest and lowest numbers and finding the middle number.