Central Tendency:Data distributed around this value in a certain manner.If even distribution occurs then it is a central tendency.3 parameters to measure. Y 3? they have distinct purposes.MEAN, MEDIAN and MODECentral Tendency and Dispersion/Deviation both are required for comparision of data.Thoda advanced level h baaki dono.Skewness and Kurtosis are also a feature.Skew data means symetrical data line se deviation hota h.Kurtosis also called as peakedness. Data Peak sharp ho jata h.Untouched data is ungrouped data.Feature:Every element will b taken into account.Grouped data is any analysis done on the data.Feature:Not all elements required.ARITHMETIC MEAN:Independent of time data is used on the other hand of time dependent data is there use Geometric Mean. Formula changes with the type of data. If ungrouped data then Sumxi/n and grouped data then sumfixi/nWEIGHTED MEAN:Indivisual weight to be considered.