Abstract
Data is most of the time considered as the plural of datum. Datum only constitutes of one element of the whole of data. Data or datum represents some information which can be quantitative or qualitative. Data represents accurate information. Mean can be defined as average, a collection of numbers under an arithmetic form whose addition must be divided by the total number on which calculation bases. Median is another kind of average, determined by the selection of one value in the middle. To treat a high number of data, median is a useful tool. Variance is defined as calculation of the variation amount of all values of one variable. The delivered information by variance are various.
