RE: What is a Box plot? and where it is used ?
Box plots is a Way to visualize data is by using a box plot or a box and whisker plot.
Box plots split the data set into quartiles. The body of the box plot consists of a box, hence the name,
which goes from, the first quartile to the third quartile, visually showing you the range of the middle 50% of your data.
see for more details on what is box-plot and where it is used