The First (Lower) Quartile is the midpoint of the lower half of our data. Ħ6 and 70 are the median values in Maths and Physics respectively (there are 3 data points both above and below these values). The median is the point at which there are an equal number of data points whose values lie above and below the median value. Now let us find the median, the first (lower) quartile and the third (upper) quartile To understand how a Box and Whisker chart is constructed, we have to first arrange our data in ascending order. Ĭheck out live examples of Box and Whisker Chart in our charts gallery and JSFiddle gallery. The Box and Whisker consists of two partsâthe main body called the Box and the thin vertical lines coming out of the Box called Whiskers. To find out unusual observations/errors in the data setīox and whisker plots are also very useful when large numbers of observations are involved and when two or more data sets are being compared.To know whether a distribution is skewed or not.For a quick understanding of the distribution of a dataset.The Box & Whisker chart displays the spread and skewness in a batch of data through its five-number summary: minimum, maximum, median, upper and lower quartiles.