When you are asked to compare two sets of data, you must compare:

• A measure of location (mean/median*/mode/quantile/percentile)
• A measure of spread (inter-quartile range*, inter-percentile range, variance, standard deviation)

*use these if the data contains extreme values

Warning

Do not use $Q_{2}$ and $σ$ together, or $\bar{x}$ and inter-quartile range together.