I have a question for my home work about finding the 3 measure sof vairability for the variable that is given to us.but i am little confuse that range, SD and semiquartile are the 3 measures or range, SD and variance are 3 measures of vairability?



TS Contributor
Standard deviation and variance are the most common measures of dispersion (variability) for data sets using the arithmetic mean as a measure of location, and for data sets where you use the median as the measure of location, a good measure is the interquartile range (75th percentile minus the 25th percentile).

The simple range (max - min) can be used in either case to measure dispersion, but it's not that great because it only uses the extremes.

...and I've never heard of the semiquartile.