Transcript Mean and Standard Deviation

MEAN DEVIATION
The range and inter-quartile range only take into account the spread, not to what extent
each figure deviates from the mean.
Figures deviate from the mean for a number of reasons:
►Results vary between regions
►Sales vary
►Output varies
THE LARGER THE MEAN DEVIATION THE GREATER THE DISPERSION.
STANDARD DEVIATION
This is used when one has a lot of detailed data; it is a more reliable measure of
dispersion.
The standard deviation measures the average deviation from the mean. Unlike other
dispersion measures it’s less likely to be distorted by rogue pieces of data.
Standard deviation can tell us:
»Are market research results what one expects?
»It can be used to find a range of outcomes e.g. batch quality, productivity etc.