Of the range and the standard deviation, which is more widely used in statistical analysis, and why?

1 Answer
Feb 9, 2015

Standard deviation is most widely used.

Range simply gives the difference between lowest and highest value, and a few extreme values will alter the range excessively.

The standard deviation sigma tells you where most of the values will be, and in a normal distribution 68% of all values will be within one standard deviation from the mean mu, and 95% will be within two standard deviations of the mean.

Example:
You have a filling machine that fills kilogram bags of sugar. It will not fill exactly 1000g every time, the standard deviation is 10g.
Then you know, that 68% is between 990and1010g, and 95% between 980and1020g, a total span of 20g or 40g respectively.

Every now and again a bag will be far over-filled (say 1100g) and sometimes a bag will end up empty (0g), so the range will be a total of 1100g.

You may decide which of the two gives a better idea of the spread in this distribution.