Box Plotting is useful technique when comparing two or more sets of data. Boxplot chart provide an instant insight into the dispersion (range and inter-quartile range), skewness (orientation of median relative to quartile) of the data. In Excel 2007 we can’t generate automatically boxplot chart, so here is a template 🙂 for you. Click Here for Box-Plot Chart Template
Why Box-plot Chart:
Suppose there is two group of data, 1st group boys score in class 9th and 2nd girls score.
Boys = 1,1,1,2,3,3,4,5,5,6,6,7,7,8,9
Median = 5
Range = 9-1 = 8
Lower Quartile = 2
Upper Quartile = 7
Inter-Quartile (upper quartile – lower quartile) = 7-2 = 5
Girls = 6,6, 5, 6, 7, 8, 6, 7, 4, 5, 8
In below given comparison screen-shot, Inter-Quartile range( difference between upper quartile and lower quartile) is smaller for girls as comparison of boys means girls are more consistent than boys.