Standard deviation tells how the data spread is around the mean. The difference between the each value of a sample and the mean is called the deviation. In other words, it tells how the common characteristics of members in a group varies to each other. This statistical model is used in almost every fields such as climate forecast, finance market research, real estate market analysis, material science, pharmaceuticals, clinical experiments etc. Standard deviation do help researchers to analyze and forecast the events through experiments, even in situations where collecting the entire set of data is not practically possible.