For instance, one pint of ordinary lager, bitter or cider, or a 175 ml glass of wine equal two units, but the UK legal limit is 80 milligrammes of alcohol in 100 millilitres of blood.
The Mean Absolute Deviation (MAD) of a set of data is the average distance between each data value and the mean. The mean absolute deviation is the average of the positive distances of each point from the mean. The larger the MAD, the greater variability there is in the data (the data is more spread out). The MAD helps determine whether the set's mean is a useful indicator of the values within the set. The larger the MAD, the less relevant is the mean as an indicator of the values within the set. Let's compare Sherlock's data set with that belonging to Watson. to see what the Mean Absolute Deviation (MAD) tells us.
In fact, the mean absolute deviation from the median is always less than or equal to the mean absolute deviation from any other fixed number. The mean absolute deviation from the mean is less than or equal to the standard deviation; one way of proving this relies on Jensen's inequality.