Or said another way, 25% of the data falls above this value. Half the values are greater than or equal to this value and half are less.
Median: The median marks the physical center of the data and is shown by the line that divides the box into two parts.Lower Quartile (Q1): 25% of values fall below the lower or first quartile value.Minimum value (min): The lowest value in the data set, excluding outliers.Here are some definitions of the elements of the box plot. The plot can be either horizontal or vertical in orientation. The box is drawn from its first quartile (Q1) to its third quartile (Q3), with a horizontal line drawn in the middle representing the median. The lowest point is the minimum value of the data set and the highest point is the maximum value of the data set. John Tukey, an American mathematician and statistician.Ī box plot is constructed of two parts, a box and a set of whiskers as shown below. The box plot, also referred to as a box and whiskers plot, was introduced in 1970 by Dr. What if you were able to describe your data central tendency, variation, and shape and compare it to other processes all with one simple graph? We will describe how this can be done with a box plot.