ABSTRACT
The branch of mathematics that deals with the collection and analysis of data is called Statistics. A typical statistical survey consists of the following main steps: collection of the data; data presentation; data analysis; and conclusions and decisions based on the analysis. The data collected is usually in the form of sets of values of a particular variable. The variable may be of two types: discrete and continuous. A frequency distribution can be very conveniently represented by two numerical quantities. One such number represents the central tendency or average value of the distribution. This is the value of the variable about which the variable seems to be located. The standard deviation is obtained by squaring the difference between each value of the variable and the mean, finding the average square value, and taking the square root of this average.
