Box plots and histograms

Since the median and quartiles split the data set into quartiles, they also split a histogram of the data into four approximately equal areas.

What does a box plot tell you about the distribution?

Centre
The median gives an indication of the centre of the distribution.

Spread
The width of the box (the interquartile range) and the difference between the maximum and minimum (range) both give an indication of the spread of values.

Skewness
The distances of the minimum and lower quartile to the median, in relation to the corresponding distances of the maximum and upper quartile give information about the skewness of the distribution. If the maximum and upper quartile are further from the median, the distribution is skew with a long tail of higher values.