'There's a huge misconception that if someone sneezes a lot then they must have hay fever,' says Dr Adrian Morris of the Surrey Allergy Clinic. From dogs to dust mites and pollen to latex, it's thought that 40 per cent of us suffer from an allergy.
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.
Absolute Deviation and Mean Absolute Deviation. Perhaps the simplest way of calculating the deviation of a score from the mean is to take each score and minus the mean score. For example, the mean score for the group of 100 students we used earlier was 58.75 out of 100. Therefore, if we took a student that scored 60 out of 100, the deviation of a score from the mean is 60 - 58.75 = 1.25.