Box Plot

Box plots are used to summarize data graphically. To construct a box plot, first find the minimum data value, the lower quartile, the median, the upper quartile, and the maximum data value. These five statistics are then marked on a number line with a box drawn from the lower quartile to the upper quartile. The median is marked inside the box.

The data set initially displayed comes from observations of Old Faithful, the famous geyser in Yellowstone National Park. The time between eruptions was measured on 112 different occasions. Notice that there are two main clusters. This behavior is explained by the fact that when Old Faithful has a particular short, less impressive eruption, then the waiting time until the next one tends to be short. The waiting time after a spectacular eruption is usually longer than average.

Data values must be numeric. You can use standard keyboard moves to delete or type a new data value. When you add a new data value to the list, the histogram and the descriptive statistics will be updated.