which measure of dispersion is the best and how?
Dear Student
The best measure of dispersion that can be used depends on the data set that is being used for statistical enquiry . Here are some instances where various methods of dispersion calculation is best suited for the particular situation :
a. If the mean is the suitable measure of central tendency, then the standard deviation (SD) is expected to be a good measure of dispersion or spread, but the median absolute difference (MAD) may also be good. The interquartile range (IQR) is always useful.
b. If the median is the suitable measure of central tendency, then the SD is unlikely to be useful , because the formula includes the mean, and if the mean isn't useful, things based on the mean won't be useful either. Try MAD or IQR.
c. If the distribution is bimodal or multimodal, no numerical measure of dispersion is going to be very useful at all . Graphical measures (box plots) are always useful .
Regards .
The best measure of dispersion that can be used depends on the data set that is being used for statistical enquiry . Here are some instances where various methods of dispersion calculation is best suited for the particular situation :
a. If the mean is the suitable measure of central tendency, then the standard deviation (SD) is expected to be a good measure of dispersion or spread, but the median absolute difference (MAD) may also be good. The interquartile range (IQR) is always useful.
b. If the median is the suitable measure of central tendency, then the SD is unlikely to be useful , because the formula includes the mean, and if the mean isn't useful, things based on the mean won't be useful either. Try MAD or IQR.
c. If the distribution is bimodal or multimodal, no numerical measure of dispersion is going to be very useful at all . Graphical measures (box plots) are always useful .
Regards .