Median is a measure of central tendency for data at the interval or ratio levels of measurement. When a set of values or scores are arranged in ascending order that value which divides the sequence in half; half of the values or scores are greater than the median and half are less than the median. In probability theory and statistics, a median is a number dividing the higher half of a sample, a population, or a probability distribution from the lower half. A median is frequently superior to a mean as a measure of central tendency when there are some scores or values which are significantly higher than all others in the distribution.

The median gives these high scores the same emphasis as all other scores while a mean gives them much greater weight or emphasis. The median of a finite list of numbers can be found by arranging all the observations from lowest value to highest value and picking the middle one. If there are an even number of observations, the median is not unique, so one often takes the mean of the two middle values. The median is one of several indices of central tendency that statisticians use to indicate the point on the scale of measures where the population is centered. The median of a population is the point that divides the distribution of scores in half. Numerically, half of the scores in a population will have values that are equal to or larger than the median and half will have values that are equal to or smaller than the median.

The mode is one of several measures of central tendency that statisticians use to indicate the point (or points) on the scale of measures where the population is centered. It is the score in the population that occurs most frequently. Please notice that the mode is not the frequency of the most numerous score. It is the value of that score itself.