Draw and describe a box and whisker plot. What is this used for?
This question has been asked previously and is covered well in previous examination reports
and standard statistics texts. Candidates with knowledge of this topic did very well on this
question. A few candidates described a Forest plot and scored poorly. Some candidates were
able to draw the shape of the box and whiskers but expressed incorrect facts regarding what
the line, the box and whiskers represented and thus lost marks.
The box and whisker plot is a way of graphically representing the "five number summary", or four parameters which demonstrate the central tendency of the data set. Correctly, the examiners point out that answering this question with a description of a forest plot would be disastrous.
Uses of this graph: